This letter acknowledges yet again (without actually saying so) that PCL is legal at an unlicensed airfield. Not many people have been aware of that.
It is a positive move by the CAA. There is no reason for banning PCL. It was, reportedly, the work of some old codger there who decided that a frequency used for voice could not be used to switch lights on and off even if it was done by pressing the same button in the aircraft.