Developers Ropemaker Properties want to demolish the premises in North Street after the store closes.
In its place, they have revealed proposals to build 92 apartments over three floors, along with ground floor commercial outlets, parking and landscaping.
PROPOSALS: Image of how the proposed new building could look
But Twentieth Century Society, which campaigns for the preservation of architectural heritage from 1914 onwards, is opposing the plans.
C20 Society caseworker Coco Whittaker said: "We believe the existing building could be sympathetically converted for residential use and need not be demolished.
"The store makes a great contribution to the streetscape and has an interesting history, being built in two phases."