If I owned/ran a licensed aerodrome in the UK, I would argue that the airfield is only licensed when it is published as open in the UK Air Pilot.
Bt definition, PCL is for use outside opening hours, when the airfield is unlicensed, probably unmanned, and therefore unregulated.
There is no law that I know of preventing use of an unlicensed airfield by an aircraft which is allowed to do so by the nature of its operation, by day or night, with the owner's consent. And there is no law which says that lights cannot be provided for such use at night. Neither the lights nor their method of operation is subject to regulation under the ANO in those circumstances.