Not possible to start without a GP signature, but as Daisy says it is possible to see another GP (although may cost you more). Chances are your local LLC will have a 'tame' GP they can put you in touch with.
Thanks for all the replies. I just didn't want my GP knowing my business really as he can be very deep and goes on about things. I know he means well but I can't be doing with it. I didn't want it on my records at all. Sounds sad I know. As it turns out there are no LL groups in my area. The nearest is over an hour away. I'm on Cambridge anyway just about but really feel the real councelling you get on LL would be of better help to me as a serial dieter who re-gains. Thanks to you all and best wishes with your plans xx