Draft proofing and reduce a CO risk

A-S have made a fair job in our Kemerton XL of isolating the back of the fridge from the habitation area for a good reason. At times a gas flame is present, if a fault develops and the gas flame doesn't receive enough air then carbon monoxide can be produced. A while back now I explored both the areas behind our fridge from outside and from inside. We had water ingress from a poorly sealed upper fridge vent and at other times I was also exploring using a fibre optic camera with a view to routing an independent power source to the toilet flush motor, so I've seen how thorough their job was here. Above the fridge there is a worktop and at the back a enclosed area which would appear to be a conduit for heat from the fridge to exit via the top fridge vent, all very well sealed off from the back of the fridge.

There was a cold wind blowing at times when we were away recently and I was surprised to feel a lot of cold draft coming from the gap at the top of the fridge, it's a small gap about 3mm but it's all along the top of the fridge. I can see there's a sort of black seal but it's not preventing air from behind the fridge being blown into the habitation area. If a fridge fan was installed low down it would slightly pressurise this space behind the fridge, high up it would act as an extractor which might be less efficient but probably safer.

My intention is to fill this gap with a strip of foam, it will stop the draft and better isolate the back of the fridge from the habitation area, and so be safer.

We have intentional ventilation installed by A-S, there are two under the single seat and externally they are just behind the nearside front wheel. I put nylon scouring pads to reduce the possibility of road spray being forced up into the locker. I also removed the metal plate baffle, but as I store our TV and laptop in this locker the vents cant get blocked.

Our Duetto also had drafts from around the fridge, yes when the gas hob or oven is being used it will need air but surely it shouldn't rely on poor draughtproofing throughout the van. In this case the top of the hob had vents which could access the air from behind the fridge. I know because my wife lost a silver necklace down the vent which was left in the van when we sold it.