hmm, you're probably right. I'm trying to avoid chopping the seat/console out if possible, but would give peace of mind (but no boat over summer).
Photos are here( can't add directly from this work computer)
steve-ribnet - Imgur
here's a pic of the console/seat (photo1). I'm trying to work out the flange arrangement - guess the seat/console has a flange that splays outwards and lies flat with the deck, then a layer of glass sits over this (no screwholes are on the inside)
There are some ominous old screwholes for the wiring loom around tank level in the side of the seat. I suspect a previous bodge-job repair has come undone... The tank sits pretty much flush up against this side (and a 1cm gap on the starboard size between the tank and the seat side at the top)
for good measure, here's under the seat (photo 2) (excuse the mess), and the gap behind the fueltank (photo 3)where fuel puddles up when the jockey wheel is extended. I stuck some plasticine in the corners to rule out a fuel line leak, and fuel is certainly running down from the side of the fueltank. A shelf has been glassed to the top of the fueltank at the front, to hold the battery (pic 4).
There's no foam padding either side of the tank at the moment. When you say 'foamed back in place' can you get fuel-resistant squirty foam stuff? I'm debating squirting this through the screwhole in the side of the seat, but it'll make removing the whole thing harder if necessary later, and probably won't stick to seal it...