Just to add to the unanimous advice remember that you can fly a G reg in UK on an FAA private license.
Will this still be true once EASA Part-FCL kicks in in the UK?
(I don't know what EASA says about this, and I don't know whether the UK has filed for a derogation on the application of this part of EASA Part-FCL. But I do know that EASA is trying to get a greater control over FAA licensed pilots flying N-regs in the EU, so I can hardly imagine that they would want to continue this practice.)