Adam
It is true that the racers in the club do tend to do their own thing (with some notable exceptions) but this is mainly because with limited time and racing and training to be fitted in there is often not the opportunity to get out on the club runs. Nealy everyone is happy to offer advice and assistance if asked.
If you want to race I would suggest:
(a) You join the club - this isn't strictly necessary for road racing but will keep Monty off your back when he finds out you're not a member. For juniors I think the cost is reasonably cheap, Phil Nash will be able to give you the details and the appropriate form.
(b) If you're going to race more than once or twice then you should join BC and get a racing licence. You can start racing by buying a day licence but the cost of that each time soon outweighs the cost of the racing licence.
(c) It's not necessary to join the Surrey League straight away. If you're going to try racing at Eastway or Hillingdon (closed circuits in East and West London) then the racing is generally not run by the Surrey League so there is no advantage in being a member. Once you've got the hang of things and want to progress to on-road (as opposed to closed circuit) racing then it would be worth joining to get access to races on the Surrey courses (although I would check to make sure they allow juniors to ride the on-road courses).
(d) If you are a junior you will also need to fiddle with your gears. There are gear restrictions for juniors (details can be found on the BC site) and you will need to adjust your gears so that you cannot use any of the larger gears that exceed the restrictions.
I also think the Club should do something to support juniors who want to race and I'm going to suggest at the next committee meeting that the club should pay for junior members race entry fees provided they turn up and ride. Whether this will be agreed we'll have to wait and see.