I'm thinking of buying a Bourton

I am thinking of buying a Bourton. I've seen a few 2016 / 2017 ish which I could afford. I notice the fresh water tank is 67 litres which is rubbish and wonder if there is a system for adding another tank underneath. I know of CAK tanks who make all sorts and if you are sufficiently well endowed in the wallet department they could make anything. I think they are made on the FWD sprinter, is that right? I believe you can't add another tank to a RWD but if it is FWD I would have thought it possible to add another tank.

Is there anything I should look for on a 2016 / 17 Bourton and were there any significant changes around that time?
Anything special I should look for - what is this I read about stress fractures and does it apply here?
They all seem to have very low mileages which seems to indicate they have been bought and run by elderly people who don't actually go anywhere in them - certainly not beyond England.

When we were thinking of buying ours at the NEC, I asked a chap from Autosleeper why the tank was not bigger. We were told that this was because the Mercedes was rear wheel drive and there was not enough room underneath. There are actually two tanks. One is underneath and there is another 20l tank in the offside bench seat taking up storage room.

At the time we were considering the Broadway, with a bigger tank, but the auto version Fiat was only a robotised manual so we plumped for the Bourton.

We had the overcab made into a cupboard and this gives us additional storage.

@pstallwood you did well to avoid the Comfortmatic Fiat, I've read a few negative experiences with them, and I have a friend who drives one for a charity. She says they can't make up their mind when crawling slowly up hill, other people say you can't get out of a muddy field. Motorhome dealers have got thousands of them in stock.
On the subject of automatics, currently there are two torque converter automatics, made by Ford in the Transit, and Mercedes (I believe) The current Fiat automatic is actually a DSG (Dual Selection Gearbox) where The Computer Which Is Always Right decides which gear you are going to want next, engages it but disengages the clutch for that gear. When you reach the appropriate speed, it engages that clutch and disengages the earlier gear, and of course selects the next gear that it has decided you will want. I had a Golf with it, and it worked very well. However, if anything goes wrong with it, dont expect a bill of less than £3000. Also I believe it needs an expensive service at 35,000 miles.

I'll look underneath a Bourton and evaluate the possibility of fitting a larger or additional tank. I think I'll email CAKtanks and see if they have a solution.
I have seen a RWD with the extra tank under one of the sofas. I don't think much of that as a solution. That makes me wonder if A/S considered the fact as a problem or not, and if they made any attempt to fit a larger tank. A lot of A/S seem to be designed for caravanners, for example using an Aquaroll to bring water to a mobile vehicle in preference to driving the mobile vehicle to the tap.
You will have seen quite a few older Sprinters with rusty back doors. They may have improved since then. If the chassis is prone to rust I will just spray it with Waxoyl.

I've just looked up Derby Motorhomes to see about a Bourton and saw this about Fiat 9 speed autos. It says they are torque converter boxes. This is the first claim I have heard, I thought they were DSG, the same as VW. Derby motorhomes' English isn't perfect (and I think their web site descriptions of Autosleepers is vomituous and pretty useless when it comes to facts) but here's the link:
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I think you’ll find the current 9 speed auto in the Fiat is a Torque Converter box. I’ve had 2 of them and they perform seamlessly.

Ah, you’ve updated. It’s my understanding that Fiat and others are using a Merc TC box.

The only Merc bit is the chassis, not the body which rusts on Sprinters. I crawled underneath the 2019 one I went to see today, and the chassis is sprayed outside and inside the box sections with some sticky rust preventative. There was no rust at all anywhere to be seen.
More importantly  I think I may have an idea to overcome the inadequate water tank capacity. This one I looked at had a spare wheel in a cradle to the rear of the axle. The associated problem of the 62 litre tank is that as it comes out of the factory I think the Bourton has a MGW of 3850kg. This one I saw has been downplated to 3500 but I think this leaves 250kg of payload which of course includes people, and 4 people are going to overload it. I can think of several ways to reduce the weight: Remove the spare wheel (? 50kg) the satellite antenna, and the rear corner steadies. Then a second water tank could be put inside the spare wheel carrier, or fixed to the chassis in its place. It would make a rather interesting investigation. If I buy it, I will certainly add a tank there and keep a 'blow-and-go" kit as I have heard it called. Personally I'm not going to change a wheel, I al too decrepit to do that.
I must look up the MIRO spec for the Bourton . . . .

The A-S manual shows the RWD Bourton having a MTPLM of 3500 kg, MRO 3043 Kg, mass of rear axle in running order 1628 kg and MTPLM rear axle 2250 kg.  This means the overall user payload is 457 kg and the rear axle loading margin is 622 kg which helps with the cantilever effect of loads behind the rear axle.  In comparison, the FWD Broadway EK LP has a similar user payload of 469 kg but a much smaller rear axle loading margin of 378 kg which I guess will be quickly used up especially if wild camping with full or nearly full water tanks and bikes on the back.  It would be worth finding out the tyre load index on the Bourton (and Broadway for comparison).  This is what TyreSafe state:

“Surveys over the years show that the opportunity for unwittingly overloading a motorhome, or poorly distributing the weight are high. To safeguard against overloading the tyres, the UK tyre industry recommends that the maximum load on an axle should not exceed 90% of the tyre load capacity as indicated by the tyre’s load index.”

This can have an impact on the rear axle load.

gassygassy wrote:... A lot of A/S seem to be designed for caravanners, for example using an Aquaroll to bring water to a mobile vehicle in preference to driving the mobile vehicle to the tap.
...

A-Ss are designed to do both - take the van to the tap and bring the water to the van.  I understand earlier A-S's only have the Whale inlet socket which won't allow gravity filling with a hand hand container.

Caraman wrote:....
It would be worth finding out the tyre load index on the Bourton (and Broadway for comparison).  This is what TyreSafe state:

“Surveys over the years show that the opportunity for unwittingly overloading a motorhome, or poorly distributing the weight are high. To safeguard against overloading the tyres, the UK tyre industry recommends that the maximum load on an axle should not exceed 90% of the tyre load capacity as indicated by the tyre’s load index.”

This can have an impact on the rear axle load.

As far as I can see the Bourton's tyres have a load index of 115.  This reduces the Bourton's recommended rear axle loading margin to 559 kg.  This remains a healthy loading margin given that the overall user pay load is 457 kg.  I believe the Broadway EK's standard tyres have a load index of 109 which reduces its recommended rear axle loading margin to 232 kg.  Although the Broadway EK LP has a slightly higher overall user payload of 469 kg (Bourton 457 kg), it's likely to reach its rear axle limits before all its payload is used.  This can only happen with the Bourton if most of its load is placed behind the rear axle which is unlikely.  

Another key advantage of the Bourton is its RWD, which will give it better traction on grass pitches than FWD coachbuilts.  The Bourton's RWD prop & half shafts and rear differential get in the way of larger water tanks but this is a small price to pay.  With ingenuity I am sure space can be found for additional water if its really required.  I would not remove the spare wheel to make way for a water tank.

Thanks @caraman that is encouraging. I would be surprised if I can't find a tank to fit underneath. The one huge advantage of carrying a spare wheel is not that you can change it in the event of a puncture, but the very fact that if you have a spare wheel, the laws of nature define that you will not have a puncture. There are two justifications - no, three, for removing it are 1) The AA study says that a car has a puncture every 99,000 miles so they are a waste of time, 2) you don't get a spare wheel on a new vehicle any longer, just a 'blow and go' kit, and 3) as I have suggested, replacing it with a water tank. The spare wheel is behind the axle so removing it would leave a huge space ideal for a water tank. Looking above the prop shaft I think there is room for a shallow tank, about 5 ins deep but it could be most of the width between the chassis rails. There are handbrake cables but  I don't see a problem, they would remain in the same place below any suitable water tank.

gassygassy wrote:....The one huge advantage of carrying a spare wheel is not that you can change it in the event of a puncture, but the very fact that if you have a spare wheel, the laws of nature define that you will not have a puncture. There are two justifications - no, three, for removing it are 1) The AA study says that a car has a puncture every 99,000 miles so they are a waste of time, 2) you don't get a spare wheel on a new vehicle any longer, just a 'blow and go' kit, ......

Touch wood I haven't had a puncture yet on our very low mileage Nuevo but over the years I have had punctures on all our cars and one of our caravans.  I haven't worked it out but my frequency of punctures has been well below 99k miles.  There are problems with the 'blow and go' kit.  Some tyre fitters won't repair the tyre if its had sealant in it, if the hole is big the sealant won't plug it, if you've had a blow out there may be no tyre to seal and it is unsafe to use sealant if the tyre's side wall has been damaged by inadvertently running on the tyre when its flat which happens.  Tyre availability can also be a problem if you don't carry a spare.  For example, you could struggle to find a CP tyre quickly and at a price you're prepared to pay.  The main reason some car manufactures have stopped fitting full size spares as standard it to reduce cost and weight.  Some manufacturers fit space saver spare wheels which are a lot better than 'blow and go' kits but these can't be used on motorhomes.