Hi Captain W...
What a start ! WP837 (C1-0720) is one of the Founder Aircraft of the 1 AEF Fleet. According to some very helpful research shared by one of the authors of "DHC-1 Chipmunk - The Poor Man's Spitfire", WP837 officially joined a dedicated fleet established for 1 AEF 24/09/1959. Prior to that WP837 was part of a pooled fleet operation out of RAF Biggin Hill with London UAS. WP837 remained with 1 AEF until 29/09/1969 then joining Cambridge UAS.
WP837 can be seen here (3rd back from the front) in an article published by Flight dated 28/11/1958 covering the formation of 1 AEF at RAF Biggin Hill.
1958 | 1- - 0834 | Flight Archive
It would also seem that WP837 is still airworthy and flying in Australia under the Civil Registration of VH-WPO
WP837 Chipmunk VH-WPO Point Cook 09-04-06
Best...
Coff.