I have just had a quick dig through Raven & Roberts and the AOTS on the Belfast, unfortunately all the full line drawings are for either 1942-3 or post '62.
However a couple of things that would involve some work.
The catapult as removed, along with one of the cranes, the remaining crane was moved on to the centreline just aft of where the hanger doors were. The hangers were turned into additional accommodation / recreation spaces.
According to AOTS
The After pair of twin 4" were removed and replaced with deckhouses.
The AA armament was upgraded by adding 4 quad and 4 single 2 pdr pompoms, were added 1 twin 20mm removed and two singles added.
From the two photographs quite a few changes to the directors, masts radars and boat fit too.
I will do a bit more digging amongst my books, in case I do find more, but it looks like you would have quite a bit of work to do, sorry.