Hello Keith
Unless the squadrons in 127 (RCAF) Airfield (later 127 (RCAF) Wing) made an unnoticed "stop" at Lashenden (i.e. not entered on their ORB's) I would presume in error, perhaps Dilip Sarkar can answer that question for you, as well as confirming the mark of Spitfire as I don't have the book and cannot attempt to advise without seeing the photo.
Below is the data on MA573 and EN398 from the link I gave to you on Spitfire production.
MA573 IX CBAF M63 403S 26-6-43 Hit by flak on low level sweep nr Cambrai 13-11-43 FH172.45 P/O L C Rowe killed - note IX and not XVI
EN398 IX 3989 CHA M63 FF 13-2-43 402S 18-2-43 416S 23-3-43 Station HQ Kenley 4-4-43 AST mods 416S 16-4-43 421S 27-7-43 AST 26-8-43 CAC ops 24-9-43 AST 83GSU 23-3-44 Scottish Aviation 22-8-44 9MU 9-1-45 80OTU 24-5-45 29MU 21-3-46 sold scrap H.Bath 10-11-49 W/C Johnson shot down 16 of his final total of 34 enemy aircraft in this aircraft
I am presuming you mean Bert Houle and not Bett? "Bert" Houle was an Ace in the North Africa and Italy -
http://acesofww2.com/Canada/aces/houle/ - In 1943 he was in North Africa and Italy, so in his period on 417 RCAF Squadron they were operating the Spitfire VB/VC from October 1942, and from August 1943 operating the Spitfire VIII.
cheers
Allan