The air danger area - D703 - is marked on the chart as having byelaws associated with it, that prevent entry. But those are the 1937 byelaws, which only apply to the area shown in those byelaws. they don't apply to the rest of D703.
They have no right to exclude you from any area outside that covered by the byelaws.
The byelaws do not prevent operation in the Dornoch circuit pattern.
Just remind them that THEY are responsible for ensuring the safety of THEIR operation, and that firing must be stopped if their operation even looks like becoming unsafe, and then tell them firmly to SOD OFF!
MJ
Ps. I remember in another life flying regularly into Dornoch. At the time there was no facility for tying aircraft down for overnight stays, and the Council were asked to install some tie down rings.
To our amazement some workmen arrived shortly afterwards and concreted two metal rings into the apron.
On closer inspection, we found, to our dismay, that they were installed about 50m apart and weighed about half a ton each!
Are they still there?