I would take a guess it was one of the B-25s used in the film Hanover Street, They were here in 1978 I believe and filmed the aerial sequences out of Bovingdon Airfield, Hemel Hempsted.
Happy New year John, To you and all the team. There will be a huge bit of Stirling by the end of 2025 looking at progress now. Thank you for the continued updates.