vasco, the way it was introduced.
The lesser powers that be had used all their ammunition to try and retain QFE from the ease of training pilot to land when the altimeter read zero, aerobatics and flying displays I suspect, and ignored the fact that in a low level regime you need to fly at a fixed interval above an undulating surface referenced to a plain surface - sea level.
That this resistance was led by the pilot mafia (I presume) and I think the navman at Northolt had something to say too (cost) transcended every command only the man at the top of the tree had the cojones to introduce change.
No single Group could go it alone and the CinC was obviously one of the mafia.
As soon as the top of the tree was ppruned the mafia struck regardless of expense reissuing all those Taps.
Regarding the mafia, and including navman, look how long it took to get Tap books.