my dad worked for British rail until he transferred over to the ferries and then went on with sealink, but when they shut the engine sheds / depot at Ashford everything was left there, and surely must all have gone to scrap now, there were lines upon lines (100's of yards of track) filled with spare wheels. I doubt they were moved anywhere.
as companies shut premises and move to smaller more compact sites, all the storage goes, and its usually left full of what some would see as scrap - others as spares, cant see people nicking whole train wheels, not the easiest of things to shift, however if a demolition contractor came in they would have the means to dispose of large lumps of steelwork.