I'm in Bournemouth - it's on the coast, but lacks any realy drama. My origins are in the North East (or Les country as it shall now be known), and the coastline there is great, but it's just WAY too far to travel from here.
Practically I'd prefer it to be within about three hours drive, which it somewhere south of Birmingham, and west of London. I suspect that somewhere midlands-ish is going to be the most practical for everyone. Not too bothered about the specific location - it'll be fun wherever.
It would be good if there was an experience local prepared to plan things, so we end up in some good places rather than spending the day driving around lost. They could also probably spare some floor/garden space for those on a budget.
I know someone who does cheap block bookings at posh hotels - if we get some rough numbers, and a rough location I can get some prices (and a nice place to stay might keep partners sweet if that's a problem for anyone).