Well, good chance this is going to be a great succes, and some guys who may not make it this time definitely want to come the second time, so it looks like a repeat around 1 september should be very likely.
I know about the kids, annoying aren't they?

Though from what I've heard at least one of them could be brought along easily enough.

I just have five cats, they can still be left alone for a night easily enough and are a lot easier to let the neighbour feed them. The money shouldn't be too bad though - flights to Amsterdam are ridiculously cheap and the trainride isn't much either. I've got some spare beds, rooms and lots of space to bunk, so that'd be just about all the costs you have. Just thought I'd mention.
Of course, you could also come separately - this event one of you comes over, the other one looks after the kids, the next event vice versa.

Then again, I could really imagine the two of you wanting to come over together and share the experience.
In the ideal world, my gf would come over to your place and look after the kids while you two (or three) come over for some racing, as my gf doesn't particularly like GT3 or crowds of people she doesn't know, but she loves kids.
Yeah, in an ideal world ...
Anyhow, I do sure hope the UK iLink community kicks off. I'd sure be hop over sometime for a drive over there no problem. Maybe ask some folks at the Man Un. Campus if they know of a space - if they do it's bound to be cheap.

Last time I was in Manchester I illegally bunked on the floor of one of the campus residents I met on the internet - their dinner consisted every day of 1 pound pizzas

- I bet they did that to save money so that they could go into a pub at 11pm to drink two or three pints only to be kicked out again at 11.15pm.

(that was in 1993 or 1994)
Anyway, by my guess the expenses for such a weekend could amount to as little as 60-70 quid for the both of yers - sitter not included. So something to keep in mind for late august/ early september then ...