Re. cheques- I'm far too trusting, last time we played in London, the organiser said that she was stuck that night and would post a cheque with the balance, and I agreed. Either I'm a good judge of character or just lucky, but she came through as promised.
I'm impressed with your initiative going round and finding an alternative venue. You took a potentially dire situation and turned it right round to a successful gig - well done. I know it left a bad taste in your mouths, but you got paid, everyone had a good time, and you've learned that next time, you need to specify a minimum stage area in the contract!