Illogical deductions:- If UK's airspace is being monitored for incoming nasty's, or ultra low flying friendlies, in either case the nasty's will fly into the wind turbines, job jibed, and the friendlies whose captains should know of these hazards at low altitude, are by definition, not competent pilots, and should be struck off. As for radar cover at extra low altitude, apart for small domestic drones around and in domestic flight paths, that's the job of the ATC, Shirley?....just a few random thoughts!
What you need is a a two-dimensional coherent X-band radar with pulse compression and advanced MTI processing,
It's not a massive problem, just increases ground clutter snd false returns which processing van learn to differentiate.
A drone won't show up on an ATC radar unless it's metallic and is in the vicinity of controlled airspace with HD radar...even then, it's likely to be classified by the SW as a bird or narrowband intereference.
Drones need the sort of radar on T45 destroyers- phased array high power serious kit that you really don't want to walk in front of.
Yeah, just invest millions and millions buying decentmilitary-grade radars for ATC, such as are found on HM War Canoes.
Just, be careful siting them near Lords and Old Trafford; we'll be worrying about fast bowlers rather than windfarms... (can you imagine the outcry if it's found that Heathrow ATC were paying off the groundskeeper to align the wicket with the doppler notch...)