I was able to find a copy at Natural History Book Service, but that was
about a year ago, so I don't know whether it would still be available.
They have a web page at www.nhbs.co.uk - they have an incredible selection
of books so even if you don't find what you're looking for; it's great
fun to look around.
Hope you're able to find a copy,
John
jford@runet.edu