Ta for the replies. I've gone ahead and installed a small-bore dip-pipe into the tank now. Been idling for a while up to full temperature with no problems (but then it always seemed to idle fine and only really drew air through when I was driving. Weather forecast for tomorow is nice so I think a test-drive is in order!
Where did you get the quick-release fuel fitting Craig? I looked everywhere for those damn things and eventually fitted a compression fitting instead (the rail being a handy 8mm).
Good luck with the retest John. Looks like Monday is going to be a great day for a drive
Richard