The tower is 52 years old. I confess I haven't been inside for a few years but a building of that age whose top floor is largely made of glass is likely to be showing its age. The eaves at least could use a lick of paint ! Then there's all the fancy towers at the likes of Newcastle, Edinburgh and Manchester. Even Bristol's looks quite smart. LBA is being left out (likewise Glasgow and Bournemouth and one or two others !
The Watchman radar is quite long in the tooth - approaching thirty years operational service. It is 4G-proof and a proven machine but obtaining spares won't be getting any easier as it gets older. I don't know which company, if any, supports the Watchman now - it was Selex not so long ago. I gather the Watchman is, by and large, preferred by ATCOs over the newer radars from Thales and Raytheon but that hasn't stopped NATS from replacing them. Similarly the Marconi S511 is all but gone from civil ATC.
The foregoing is wishful thinking from a layman. I'd be interested to read any professional opinions on what I've said. I'm not saying I'm right necessarily, just what I feel.