This scenario of woman falling from a horse frightened by a low flying helicopter is not unique. I was on a legitimate low flying training sortie within a low flying area and after passing low over a tallish hedge noticed out of the corner of my eye a rider falling off a horse. Fortunately the rider was only shaken. I called an ambulance and the police were in attendance. The investigation went on for months and I was under constant harassment by various investigators. It was a very upsetting time for me.
The mention that the Health and Safety Executive are on the war path is frightening. HSE have more rules and more power than is reasonable.
My hope is that the senior officer will do his bit and that will be the end of it.
My sympathies go to the family of this tragic event, but like A and C believe that those who chose to participate in risky past times/sports/leisure persuits must accept the associated risks.