Excellent news, however I don't think Signature have lost much business to Harrods ... on the contrary I can think of a lot of business that has moved in the opposite direction. Nevertheless, the current Signature facilities are certainly sub standard to those offered by Harrods.
Stand 51 - this hasn't existed for a couple of years at least.
The "MiniTower" - I understand that this will be demolished. Since Apron Control was disbanded 3 (?) years ago and those functions transfered to the bunker, the building has only been used as a base by the Marshallers.