There needs to be some sensible policy guidance on this, if objections are raised at the planning permission stage it is far too late.
There is likely to be a tolerable interference level which can be filtered out or localised, acceptable from the perspective of the air defence system.....multiple radars, E3 gap filling etc can cover when needed...add to that operator training, to watch for that suspicious plot entering the wind farm zone!
Of more concern would be interference in overland and low flying training areas. There is a case for keeping wind farms distant from these areas for very understandable flight safety reasons!
Is there further information in the public domain? I think I grasp how the interference or spoofing would occur, but to what extent? How similar is the doppler shift from a rotating wind turbine blade to a fast moving jet aircraft, for exampe? How big are these blind spots? What is the position of the CAA? As I understand it they require consultation on windfarms within 30km of an aerodrome.