Now let's cover the various airframes your Mum would have flown (those advised by you so far that is).
Firstly I must give due credit to Messrs H Shields, R Brown, J Goncalves and R Blievers for their help by way of their splendid book 'Chipmunk - The Poor Man's Spitfire', also B Fisher and his publication 'Chipmunk - The First Forty Years' (Published in 1986), in providing the following summaries. I have supplemented with my own research as appropriate.
Referring to the pictures you have posted, WP801 is the only airframe readily identifiable. The airframe showing 32 on the mid section of the fuselage is almost certainly a RFS airframe but I'm unable to tie it up to a Serial Number at the moment.
WP801 (C1-0683) is now under Civil Registration in the US as N801WP and is still airworthy and based in Montana.
Following service with the RFS, it would appear WP801 joined the Royal Navy and sported the Cowl Number 911.
Image Credit : M Freer
The picture you have posted is historically very interesting. Firstly you will note that she is flying without Spinning Strakes and the Spinner removed. Spinner problems plagued the RAF Chipmunk until late 1950 when the Spinner was removed permanently and the Backplate retained to duct cooling air into the front of the engine. A later mod corrected the Spinner problem.
The picture also shows the 'Two Stage Amber' screens on the sides of the front canopy perspex ... when in use the Front Seat student/pilot would wear complementary Blue Filter goggles to undertake IF training ... but that's another story
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