The 1876 building was designed by G B Hart, and is in line to be pulled down and replaced by a new scheme by David Chipperfield Architects.
Adam Wilkinson of SAVE Britain's Heritage, said: 'The existing buildings contribute positively to the conservation area and there is no real reason to pull them down.
'The proposed new building really isn't an improvement on what is already there - rather it seems to ignore all the lessons of the last 40 years. It must not be allowed.'
The decision will be announced on 23 July, and if Chipperfield is granted planning it could see a new 97-unit project that will maintain some of the existing building's facades.