I'm doing my birthing centre classes at the moment Ryn, and while I still have more to go, so far I've seemed to know more than average, and I think that's a combo of books & belly belly, which allows me to ask my midwives informed questions. And one of my birth support people is a student midwife, so I can get her to find things out for me as well.

I think that the hospital classes are invaluable for finding out what to expect, what their values are, how they do things, what their policies and statistics are. And general info.
But I do appreciate that it would totally suck to pay for extra classes where you find info that you've already researched for yourself.
Can you call the NCT people and ask them what they cover in their course? They might have a week by week breakdown of what they teach that you could check out.

Sorry I can't help you with some more localised info! Good luck figuring it out!