I've just bought some books, I noticed you can find them on ebay but they are older revisions, also a good point to note is that the new revision has no mention of Trevor Thom on there, I don't know if he has quit but I'm sure it could cause confusion when everyone says Trevor Thom
The ISBN is 1-84336-064-0
that's book 1
Revised and edited by Peter D. Godwin, 2005 revision with the new JAR and NPPL stuff added
Good Luck
Ben