It's funny you say it went into too much detail for ITEC.[:-]
I think it depends where you study. I was taught by a man who taught A&P at college to A Level students as well as us lot (he preferred us of course!) He was a fountain of knowledge, there wasn't much he didn't know - about all sorts! Bless.
He taught us to a very indepth level, which I am glad about, but I think in a way he made it harder for us. I have just studied at another college and their approach to the subject seems to be much lighter, skirting over stuff.
Personally I need to understand things fully to really get to grips with it, so I probably made it harder for myself right?
We really did work hard at the a and p stuff, in fact we had to do it twice, only could do the massage after we had done that first and then repeating it again, so I had to do two exams in it.
I don't think the Helen McGuiness books go into enough detail, but I know plenty of people who have used them and passed no problem. I think it is down to individual taste and how deep you want to go into the subject.