Trying yesterday to rub the corrosion marks down a bit more and I have discovered what looks like rust in one of the areas on the outside next to the edge trim .

Is the frame of the Puck L gas locker cover made of steel? That can only be the reason which means a more urgent attention.

It could be some of the screws, when I re did my herzim trim I replaced mine as some had gone rusty

Thanks yes, will need to take it all off I reckon. Need plenty of time these day therefore maybe after our next trip which is next Saturday for about a week

Hi Hampshireman, did you resolve this issue?
I’ve got the same problem on the gas locker door of our 2006 Triton. Mine has a different finish, in the sense that it is like a ‘ribbed’ effect, rather than dimpled.
I’d like to have a go at it myself if possible, but won’t mess up the look of the van for the sake of a few quid.
Thanks,
Russ