In the recent review and changes to the low flying rules, one option of restricting all flights to a minimum of 500ft above the surface as per the ICAO standard was considered.
Most objections to that idea were based on the requirment for regular practice of forced landing procedures and the CAA agreed that it was benificial to safety that flight below 500ft asfc should be permitted.
The CAA has also in general guidelines to instructors following certain high profile cases insisted that it expects instructors to be able to plan and execute training which involves descent to heights less than 500ft above the surface on a regular basis without any question of endangerment.
That is why I said that before operating at low level, one must ensure that the proposed operating area or route is clear of people and livestock and especially people sitting atop livestock!
Ask the guys at Odiham about hedge hopping and getting a bit close to someone sitting astride livestock!
Regards,
DFC