SASless,
Further examples of eccentric British military altimetry procedures:
1. Transition altitudes lower than MSA.
2. QFE.
3. "Clutch" QFE - requiring an approach to be flown using the QFE of a runway at a different aerodrome.
The defenders of these practices often say something like "it works well for us, why change it?", a point that has some validity but fails to acknowledge that standardisation with the rest of the world is a valuable objective that promotes safety and aids interoperability.
That said, the same argument can be levelled at using inches Hg instead of hPa.