The largest move is to decarbonise. We remove the gas boiler that served every flat and heat the building instead with four roof-mounted air source heat pumps, their pipework run down to each flat through the existing chimney breasts. A new communal stair runs beside the building's windows for the first time, giving a long-dark core its own daylight; the relocated lift opens directly into the flats. Windows are reinstated as single glazing with laminated acoustic glass to keep the historic fenestration, with secondary glazing behind cutting heat loss and noise. Inside, we recombine some divided flats, joining the ground floor to the basement below and the top two floors to each other, so each home regains the scale and light of its principal rooms.