THUMS Spitfires
Researching something else, I've come across references to THUMS: Temperature and Humidity of the Upper Air Masses. These seem to have been instrumented Spitfires operated in the 1950s, providing data direct to the Met Office, and not part of the better known Met Research Flight, then at Farnborough.
Registrations I've found reference to include PS853, PM628, and PM651, and also references to a fatal accident in PM628, and operations from Woodvale.
Does anybody know anything about this - it's new to me, and quite interesting.
G