If I recall, all four engines were removed from the Hendon Fortress when it reached it’s destination after the trans-atlantic ferry. Flew in formation with Sally B on arrival at Duxford – first time I’d seen two Forts in the air together. 1982 – I think. I recall the engines were very low-houred, and would be wasted on a static aircraft, so two were hung on Sally, and two on Mary Alice ready for when Sally needed those. Two static and two nearly time-expired engines went down to Hendon. !!

Very close…as I believe it was 83.
Eng No’s 1 & 2 were indeed changed the same year and 3 & 4 were swapped on M A as spares for the future.
However not all the Hendon engines were low houred and I believe No.1 was immediately swapped again the following year in the winter of 84.

I have a recollection of one of Sally’s spares on Mary Alice might have been used during “Memphis Belle”, but unless I’ve got the dates wrong that would be seven years later, so if true the engine would have needed a bit of work!!

Again you are very close as it would actually be 6 years based on the dates involved.

Bomberboy