I'm a
RYA Yachtmaster Instructor &
Dinghy Senior Instructor. I've no specific recommendations for the SW (aside from saying it's a lovely place to sail) but I would also encourage you to do some dayboat or dinghy sailing, alongside the cruising courses. It's much harder to learn how to really sail well in a cruising boat than a dayboat/dinghy. The loads are greater and there is much more momentum in the system which both reduce the instructor's opportunity to allow you to make
mistakes (from which you learn) and the boat's responses to your actions are less immediate, and thus harder to recognise. There are plenty of things you can only learn on a cruising boat, but
small boat time will really help.
If you get some experience, and manage to get out for a few weekends on other boats, there maybe little need to do a formal comp. crew course, as long as you go into the dayskipper with the right attitude (i.e. that there's lot to learn!).
Final
advice, is for cruising courses the instructor is more important than the
school. Find out what the
school looks for in instructors, and what their attitude is. The RYA allow 5 students on a boat but most of the better schools choose to operate with 4. Perfect shiny boats may look good, but how many (minor) berthing
mistakes will they let you make? I'd even argue against
furling sails on a
training boat - everyone should know how to get a headsail up and down. Needless to say I have a
furling headsail on my boat!