Alex -
I searched the East Anglia web site (
http://www.eastangliabooks.com/search.htm ) but could not find the book or any other listing by an author named Thomas.
The book you want is:
Thomas, Geoffrey J. and Barry Ketley. KG 200: The Luftwaffe’s Most Secret Unit. Crowborough: Hikoki Publications, 2003. ISBN: 1 902109 33 3. Hb (oversize). Dj. 192p. Heavily illus. Color profiles. Appendices.
Note that this is by Geoffrey J. Thomas. Note the different page count. The other author is a G.
T. Thomas and I have never heard of him.
Larry