I could see the lower being kept, but with a lot of work on the councourses, etc. I'd be amazed if the upper isn't pretty much completely replaced, it has so many problems.
A shell around the north was easier because it had all the old office space that could be repurposed, the DE is all squeezed into the smallest amount of space they could manage. It'll be interesting to see what the plans are for the gantry up there, I can't imagine it not getting a massive upgrade because it's very basic right now.