So are we talking about a low pass over the airfield (Bolt Head aka Salcombe on SD) or a low pass over the landmark known as Bolt Head?
The pilot may have been lost and looking for a landmark or may have thought he was making an approach to another airfield (been there, done that).
But as for "no-fly" zones, this is something I have had heated arguments about before with so-called "controllers" at remote grass strips. By the look of your website, these are areas subject to a local agreement to placate your neighbours who don't want low flying aircraft over their houses every 5 minutes. Theses areas are not mandatory, they are not marked on the charts. The only sanction you have is to insist that the zone must be avoided otherwise you will not allow an aircraft to land.
As for the feckwit in a C130 at 300 ft that flew through the circuit of my local grass strip (also marked on the charts), no-one would even acknowledge it happened when I phoned around to complain.