Bourton hab door lock replacement

I have mastered the job of removing the panel, and rotating the inner pull handle. That's easy.
Now, I have found that the lower door latch mechanism has a broken spring. I have tried to stretch and bend the remaining part of the spring but I failed. This is a complex spring which cannot be replaced simply from a box of assorted springs you might buy from ebay or Aldi. I doubt that a replacement spring can be obtained, unless you work in the Fab Firenze factory. Does anyone know where a complete latch assembly can be bought?
The label on the latch reads:
FAP FIRENZE
1126 UP 4511
Rev1 29/01/2019.

I have emailed O'learey motorhomes, as they have several hundred doors for sale, and I have looked on Ebay and the only thing available there is a £208 complete solenoid with operating mechanism, but that is not the actual latch.
Meanwhile I can reassemble the door and keep it shut with just the top operating latch working which is better than nothing. If I can't find the latch mechanism I'll have to fit one of those Fiamma external door lock flaps.

Is this a Hartal door?  AS list some springs for Hartal....

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Oh that's wonderful ploughlin and paulmold, thank you. I didn't think we could just buy the spring. That bottom catch spring is exactly what I need. I'll find the price and if it's reasonable I'll get a couple for the top and another couple for the bottom catch, as I suspect that they might go again. Or to put it another way, the way to prevent it happenning again is to have a spare! Thus speaks a motorcycilst who used to carry a spare set of cables, then they never broke!

Only thing is I have just this minute been informed that tomorrow morning we are off on a mediterranean cruise, talk about a last minute dash! so I won't be able to fix it till we get back. I'll call A/S before we depart and get a price and ask them to send them while we are away.