Nutloose, you clearly missed the secret Infra plan when you were in.
Let us take a simple example. OCU 22X is located on a hangar annexed at RAF Y. The building isn't very good but they have managed for a number of years so clearly the need for change is low. RAF X is losing its resident sqns and offers other advantages so OCU22x is moved but the facilities are not perfect and it ius necessary to refurb and expand the facilities.
Meanwhile back at RAF X . . . you get the drift?