The CAA is mainly concerned with the effect that large wind farms have on aerodrome radars. But the the CAA and the ICAO will have guidelines on lighting of tall structures, especially those within 6km of an aerodrome.
CAP 764 is the publication that details the CAA requirements for wind turbines.
However, it is worth noting that the CAA does not govern military aviation and that military aviation does not always follow the same guidelines as civil aviation. In such cases the MoD will have their own ideas on safety around their airfields.
Defence Estates are the people to contact.
I would suggest that if you've been asked to put a light on it then its proabably a good idea unless you want it knocked down by an aircraft.