Aircraft serial F715 falls in a block F701 to F850 of 150 Vickers F.B.27 Vimy's. Only 12 were completed by Vickers at Crayford. It may be genuine, but is not from an SE 5a. This information is from British Military Aircraft Serials 1912-1963, by Bruce Robertson.
Dwight: All SE 5 serials are in the Axxxx range; SE 5a serials start at B1. Most of the SE 5's seem to have gone to 56 Squadron, starting in April 1917; some of them were still in use in November.
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