Fuel leaking :(

Well after all the work I've done on it, the GS fired up this evening and seemed just fine. I took it to the local Sainsbury's and filled up with unleaded and then went home - 10 miles or so. The bike felt like it was running nicely.

The only problem is when I got home I could smell fuel and after taking the tank off found quite a pool in the tank access port lid. I mopped it up and it immediately started oozing out again - you might be able to see in these pics: http://imgur.com/gallery/EE7lh

So I'm not too sure what the problem is (other than fuel not staying where it should). I am wondering if the tank access port lid (on the back of which is mounted the fuel pump etc) is somehow leaking. Some thoughts:

• it seems to only do it when full as there was 5 or 6 litres in when I went to Sainsbury's and it wasn't obviously doing it then
• the fuel hose isn't leaking as that would (I expect) be a fair spray and that's not visible when the engine is running
• the leaking doesn't appear to increase speed when I have the engine running
• the damp line seems to ooze from the area around the lip round the fuel pump ECU housing but inside that was dry when I took the ECU out
• it's coming out at a fair rate as the fuel access port lid was full when I got home

1,212 curses. Next job seems to be to get another lid & seal and transfer the fuel pump etc from current to replacement and see if that helps.