Hi Huw,
Thanks to Peter for the URL, also this URL will put you in touch with the Radio Society of Great Britain (RSGB)
RSGB on their site there is a link which lists all the local radio clubs, most of these clubs run a foundation course, but as you have already passed the RAE you will only need to pass the 5 w.p.m. Morse test again these clubs would help I'm sure.
Mark (Muttley) G0TMT, who posted earlier, would be able to tell you more as he is a lead instructor and probably has more info than me.
I took my RAE exam back in the days when it was chipped into tablets of stone, I'm glad to say it seems much easier these days to gain entry into the hobby, this is because we were running out of people to talk to. Since the foundation licence there has been an influx of good quality radio amateurs now on the bands, thanks to the hard work of people like Mark G0TMT.
Good luck, Huw mate, or should I say 73 from Paul. G4LNA.