I can't be arsed to read the whole thread so apologies if this has already been suggested....
Why are you wasting time and effort by doggedly carrying on with a mission for a single, centralised venue?
LZ does shows, yes?
Bath and West and Billing wasn't it?
At these shows you've paid for your pitch, the pay and play is already sorted, so are the toilets, campsite etc, insurance isn't an issue or any other liabilities for that matter.
So why not just piggyback on another show - there's no limit to numbers who can go, all the hard work has been done for you and you can just party, hard! (And Fanatic will be happy)
The LZ stand could have a big banner on it for the season saying
"Landyzone, celebrating 10 years, 2004-2014" or something on those lines.
I know it's not centralised and it'll be regional but I bet you stand a good chance of getting more people to participate that way.
It's cheaper and already utilises resources that you already have whilst making use of those already paid for at a show - cost effective, less hassle and to quote Pikey "K.I.S.S." (Keep It Simple Stupid)
Just an idea, I'll get back in my box now, happy new year!!!