The Imperial War Museum
www.iwm.org.uk

Sez-U Theatre
www.sez-utheatre.com

The National Collection of Aerial Photography digitised over 600 camouflage photographs of the 1PRU Unit and made them publicly available:
http://aerial.rcahms.gov.uk/database/results.php?search_term=*camouflage*

They also created a collection level description for it:
http://aerial.rcahms.gov.uk/isadg/isadg.php?refNo=GB_551_NCAP/4

Suggested Reading:
Camoflague and Art: Design and Deception in World War II, by Henrietta Godden, ISBN 0906290872 (Unicorn Press)