Erect additional floor to existing building and part demolish and re-model existing 2 storey rear projection to form part single part two storey projection with terrace above single storey and change of use of extended building from retail (Class E) to bar at basement and ground floor level and Student Accommodation Units (Sui Generis) to first, second, third floors, install external staircase to rear and alter elevations (Part-Retrospective)