This is the L shaped hose below the heater tap that joins onto the pipe that runs up to the engine.  1979-1981 Silver Shadow II, Wraith II & T2

This is the heater return hose between the engine and the pipe that runs up to the heater matrix. 1977-1980  Shadow II, T-2, Silver Wraith II, Corniche, Camargue (VIN 30001-35411)

This is the heater return hose between the engine and the pipe that runs up to the heater matrix on the later. 1978 from VIN 35279 Continental, Corniche, Shadow II, Silver Wraith II, T2 onward