Intersango seem to be having problems with their UK bank account (statement says they will be closing it at the end of the month) so perhaps best to wait until they have a solution.
https://support.intersango.com/statusYep, I mentioned that. Only a problem if you plan to make cash withdrawals through them, which should be easy to avoid if you have an account in MtGox as well for instance. Intersango's GBP market is about as liquid as MtGox-GBP, maybe more.