It was a long time ago, but I agree with WID62's settings for the RAF Brits. I think these engine ant-icing valves were called the Fore Skin Jets! However the civilian Brits were a bit different. IOAT was +12 to 0 degrees when the B Skin Jets had to be switched on. I seem to remember the engine ant-icing system worked a bit better on the Civil Britannias.