Ah yes, I guess that explains a lot. Saw lots of work going on there recently. Looked like they were removing/relaying some of the sidings as well as stuff inside the buildings.
Disclaimer - rant ahoy
Essentially the whole depot is being rebuilt. 16/17 road have been gutted and are being extended and rebuilt. 14 is being extended to full length, 12 and 13 are being kitted out for the new trains. Entirely new stores and office facilities are going in. Fuelling locations have to be moved, CET has to be put in, the yard has to be reconfigured, old sidings removed and new track laid in the Wensum triangle. Oh and then it all needs to be commissioned.
Needless to say all the change has affected maintenance both practically and operationally. The reinstatement of Colchester to provide additional DMU maintenance capacity should help a little but it's no small job.
Something to keep in mind is that nobody WANTS to put anything that doesn't look acceptable into service however with the fleet so stretched sometimes it's sometimes a case of just ensuring the fleet is provided in a safe state and availability met. Also sometimes things will happen between trips to depot and again with it stretched in such a way it's hard to pull vehicles for relatively small issues like some luggage rack carpet which would then result in a cancellation.
I have every reason to believe that the new units will be kept in better shape but it's anyone's guess how they will be in 20/30 years like the 15Xs/Mk3s when they'll be replaced in turn.
Just my two cents.