Needing a license to fly models in the UK is news to me (unless you are flying VERY large heavy models which need an exemption certificate)

Used to need a license for the radio control (20 years ago when I started) but that has not been required for many years now.

Assuming you are serious about model flying (you are prepared to throw £200 at the hobby?) then it makes sense to join the BMFA and get insured. It also be a good idea to find a local club and take advice/help from the experienced members, living in london need not prevent you from doing this.

Where in London do you live?

Simon.