Doesn't need to be a Turnhouse based Spitfire. Not a million miles away was RAF Acklington in Northumberland. No72 Sqdn, Spitfire equipped was based for eight months in 1940, before departing for Biggin. No610 arrived from Biggin as 72 left, also Spitfire equipped, a Canuck could obviously be flying in the RAF at this time. It could (if true) be something like this that went pear shaped, but like others the original story seems 'odd' to put it politely ...