Rear cupboard door under sink

I am hoping that someone has come up with a clever, simple solution to stop the double cupboard door under the sink of my Lancaster (Nuevo EK) from opening when I apply the vehicle brakes. The magnet that holds the centre joint of the double doors does not provide enough force to hold the centre joint closed, which allows the double doors to fold and pull the catch loose on the left hand side allowing the doors to fly open. 
I have tried putting extra magnets on, but these have pulled off. In the meantime I have to secure the door handle with an elastic strap to the adjacent cooker handle when the vehicle is in motion.
Personally I find that the double door gets in the way when we have been shopping in the supermarket. I stand outside and pass up the food and wine provisions to my wife, who puts them into the cupboards under the sink, where we have  a couple of stacker boxes that fit into the cupboards. To get the boxes in or out of the cupboard the double door blocks the side door entrance!
I think I have read somewhere of converting the double door to two single hinged doors.
I am sure there is someone out there who has had the same problem as me and has managed to fix it.
Phil

My van came with two single doors as standard, as I thought all EK Nuevo's were. But they are fitted with full length piano hinges. This is a bad idea as they barely open 90 degrees, and really get in the way. So as a mod I removed the doors and fitted double throw hinges as fitted to some kitchen unit doors. This means the doors open almost 180 degrees and give full access to the space.
Al.

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I used these on the bathroom vanity sink unit doors on our Broadway EB.

John.

Perhaps you could try a small rare earth magnet. They can really have some clout but you should be able to find one to suit.
Found this website.

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Hi Phil

It's probably not a cost effective option, but the drawers as fitted to the later Nuevos are vastly superior, so it might be worth contacting A/S for a price!!  

We also found that double door a flaming nuisance, and the difference now we have a later van is quite significant. It seems trivial, but it was a pain in the backside on many occasions.

Thank you all for your comments. 
I have ordered some of the catches, which look like they might be the solution. Thanks for the link John.
I have already tried extra magnets, but the adhesive was not strong enough!
I will just have to put up with the double folding doors, as long as they stay shut when I brake!
Phil

Use a turnbutton catch, similar to those used to secure small table in wardrobe. They fit between the cupboard doord and the drawer above. Lock across top of door near centre hinge and hey presto.