What I don't get is why the current situation, before this wind farm is built, where a non-transponding light aircraft can climb into the TMA in this area and controllers will continue to assume it's remaining below CAS, is deemed acceptable, but a future situation, when the wind farm is built, and non-transponding aircraft still climb into the TMA, is considered unacceptable.
I expect they will get lots of returns from the wind farm and would like to distinguish between real aeroplanes and clutter from the turbines.
I don't mind, my own personal view is that every aeroplane should have a transponder.