Surely, (engaging pedant mode) applying the letter of the regs, cadets and staff can't wear leather soled shoes in no.2 dress? Oxfords are authorised for no.1s, (but I don't wear mine as they refuse to polish as nicely as my DMS), but only DMS shoes are authorised for No.2
DMS means Direct Moulded Sole, so can only be made of rubber?
I don't particularly care, but it is an interesting thought.
Personally, haven worn Ammo Boots for re-enactment purposes and film extra work, I wouldn't wear them in the ACO for love nor money. Awful things.