Also, what are the steps we have to take to becoming a charity - can we similtaneously form and register?
See http://meta.wikimedia.org/wiki/Wikipedia_and_UK_charity_law and http://www.charitycommission.gov.uk/publications/cc21.asp#3
I think the first step should be to start working on the bylaws, and then see what needs to be included to ensure the chapter will be eligible for charitable status.
The Italian bylaws would be an excellent starting point. They've picked the best parts from the French and German bylaws, learning from the experiences those chapters have already had, and these were recently approved by the Foundation. There's an English version at http://meta.wikimedia.org/wiki/Wikimedia_Italia/bylaws#English_version
Angela.