Thanks again Genghis.
Conflicting with other airspace uses isn’t really a practical problem as the drone is likely to be used from either the base of a mountain or if I am lucky and there is a road to take off from there. The main concern is of low level shear, say 200ft AGL, above which my reserve parachute would probably open in the event of a collapse.
The rules of the air state minimum altitude of 500ft except for a glider hill soaring and it is this chunk of airspace that is critical for us.