Thanks, folks! With these answers plus offline guidance from bookworm, I'm now clear.
I find the UK AIM infuriating - everything's in there, but unless you know the answer, it's a devil to try and find it. The index is zero help. It reminds me of early computer manuals - designed for the expert to refresh his memory on the precise details of specifics; little help to the enthusiastic student who wants to learn.
But, AB, rest assured the dissertation will be finished before any work on indices...