Tim - thanks again, but (not that you'd know this) part of the reason I'm doing this job is to move the 'centre of gravity' of the boat a bit further forward. The old helm was too far back for 4 divers & kit and the boat was too stern heavy. So.. the new console will be pushed as far forward as possible and will be up against the fuel tank - even if there were a hatch, there wouldn't be space to get a sponge in there.
Nos - thanks too - that's the sort of solution I'd considered, but I was just wondering if anyone else had taken the same approach
To be honest, i've considered both the 'hatch and sponge' and 'drain' options, just looking to see if there's any consensus, or any other good suggestions