Hi
Try getting in touch with your local Chamber of Comerce, they should at least be able to put you in the right direction.
There are indeed leaflets available that gives busines start-ups info on their own industry, it's very basic stuff, but it's a starting point. And yes they do have info on mobile discos...ask your bank for the relevant leaflet.
You're doing exactly the right thing anyway, getting to grips with your business plan, that will show a bank manager that you have enough nouse to do the job.
if you're looking for a bank that won't hastle you, try HSBC, in fact they will hastle you in such a small way they might as well not be there...bloody useless.
I work for Barclays, but can't comment on their business section as I'm a personal banker...yes I said banker!
they have their own website dedicated to businesses though, check it out at
http://clearlybusiness.barclays.comHope that's the correct addy

Good luck
Darren