It's interesting how a company once so mighty and important can be reduced to just 2 floors of office space in a small portion of a building once wholly occupied by them! And that's nothing to do with technology changing form!
It's also interesting how quick it all happened with Central. Around the turn of the century they were still quite a substantial network producer, they had the networked CITV stuff, own transmission operation, 3 local news splits...and just a few years later most of that was gone. Other regions have either had a slower decline or never did that much in the first place. I think it must have been a casualty of the Carlton side of the merger as Leeds and Manchester did much better out of it.
As someone else has already said, the Carlton-Granada merger came on the heels of firstly ITV Digital's failure, then Crossroads getting axed, leaving Lenton Lane very empty. Had Crossroads been a success I imagine Nottingham would have been kept on as it was taking up the lion's share of studio space at one point. That said though, it's fair to say the network never really gave it a chance... possibly for that reason?
I agree with you though - in 2001/2002 they had Crossroads, Barbara, Peak Practice, a number of gameshows, CITV, 3 news programmes, the regional productions etc. plus more I've probably now forgotten about - all that virtually gone in 3-4 years.