They might not have much of an impact on property values (certainly no more than the plethora of existing building regulations). But we shouldn't be surprised if as a result people vote for a candidate whose campaign promise consists of picking up a grenade launcher and blowing up windmills.
Even moreso now, because PV is now cheaper per square metre than tiles or fences, even if you don't hook it up to the grid afterwards.
On the other hand, this is the UK so maybe. They did Brexit and somehow Farage hasn't been deported for the consequences.