I think you need to apply for a non race national b license. This is just a registration formality that costs thirty quid or so. If you want to go circuit racing then you'd need a national b competition license which will entail a practical assessment and a written exam.
Cheers, its when u start needing to cough up for another visit to the opticians and try and get an appointment at the doctors that it starts getting more like hard work and expense haha! i'll be looking into the b licences then ;-)