External alterations to the existing building, including the part demolition of the existing roof and rear facade and erection of a new roof extension and extensions to the rear at floors 1-6; installation of a new plant enclosure at roof level; works to the front facade including stone repair and lowering of principal entrances and other associated works; change of use of part ground and part lower ground floors from Class B1 to flexible use for either Restaurants and Cafes (Class A3), or Drinking Establishments (Class A4) or Office (Class B1); other associated works.