Just a point , even when aircraft are stored they still have to move to stop breaks sticking, tyres getting out of shape and as you probably noticed over last couple of years aircraft were
flown on circuits quite regularly by Jet2,TUI, Easy and Virgin so need to parked where they could be got at even the TUI MAXs moved and had the engines started
Runway 23L has been used when maintenance was done on 23R and in a few emergency situations.