Nice one Sue, you found one more book than I did on Amazon

I read the review of that book and it said about the aqualog series:
'They are in the main a fish identification encyclopaedia and nothing more. But for those aquarists who are particularly interested in a single species they are indispensable. '
Like you say, it is quite expensive. If it was cheaper I would probably buy it, but as it does not look ideal I will pass.
I am not hopeful, but I will keep looking. I will try out my local library and a couple of bookshops and let you know if I find anything.