The use of QFE for the RAF makes sense.
They still find it bearable to fly on QNH only when abroad, come to think of it, as far as I know all their tactical flying is done on QNH. Why use QFE for recovery?
I know "...fighter pilot - pea brain..." but still
I trained and worked as an ATCO in Sweden, and their air force used QFE. It was a real pain in the @rse, the problem growing with the AD Elev. A fighter at 2000ft could be 1200 above a B737 at 3000ft......QNH.
(Because no sane airline accepted to fly on QFE)
Big dark hole ready for ATCOs to fall into? You bet.
Student pilots that are arithmetically challenged should IMHO not be let outside the circuit, or lack of understanding of the altimeter would see them meet Mr. Cumulus Graniutus fairly soon.