I was a member of the DCA, and am a member of the OGA, also am still a member of the Tideways TOA.
The boats I sailed at the time, wooden BR17, Tideway12 and 24 ' MK1 Cornish Crabber , GP14, were all 'allowed'
I only used the BR17 or TIDEWAY ON DCA trips, more creek crawling than sea going, although the BR could venture in more coastal stuff. and I slept on both.
The only racing was in the Tideway ,pursuit race, where a handicap was necessary.
the rig of my BR was a gunter sprit. Tideway a gunter, Crabber a gaff cutter'
I found the DCA a great bunch of individuals and very adventurous.
I now mostly sail in the Bristol Channel and West Wales in the Crabber and Falmouth work boat , Heard 28.
The OGA have a good programme for group sailing in the Bristol Channel area, and the small boat section have a number of events here.
DCA rallies are UK and Europe
Trailer sailers suit the DCA more, but if you want to race join a club.
There is a BRE that races at the club, and he definitely has a handicap rating, my old BR17 also races here, (Cardiff Bay Yacht Club)
Steve Jones ex BR17, STORM17