It's just thier minimal manning at the main UK hub will not allow aircraft to return early even when empty when techies would dearly like to get there hands on them.
So - the Independent Free Nation of Movers decide on the manning levels at the APOE, so they are at fault when unplanned movements can't happen? Last time I checked, OC APOE Wg (Movs qualified Logistician) worked to the Stn Cdr - or is there a secret cabal (probably zionists in tin foil hats) that misdirects and means the Stn Cdr isn't in charge?