I too will join the "if it helps making up the numbers, I'd be delighted to come; if it's overscribed though I'll happily give up my place" camp.
This time it would be cool if we could organise a social/drinks session in the evening as well (informal, of course.) Last time, the security guard at the plant *very* kindly drove some of us to a local pub to continue the evening - it would be good if we could get more out this time (but obviously organise it such that we don't need to impose on the staff to give us a lift this time

.)