Sven Sixtoo-None of the Air Ambulances I know have been constrained by county boundaries, in fact they are generally keen to expand their exposure and hence revenue gathering potential. They are tasked by Ambulance control, not by the charity, by and large. So they could be brought in to play in any National Emergency as seen fit by Ambulance Control. Yes it is something that could be tidied up but if the Government gets involved costs will spiral, serviceability will collapse and we will have more civil servants than front line staff.
As for a charity funded SAR Helicopter, ask the RNLI about that.
Can not comment on Civilian/Military registration as I don’t know. Would suggest that getting dispensation for Civilians to fly to Military rules would be harder to get than an NVG clearance from the CAA, as by law we have to comply with CAA rules. Also you have to look at the engineering side, another can of worms. Not aware of any precedence in the UK for Civilians Flying Military with this complexity, in this country. But there are several units that have G registered aircraft flown by Milatary/Civilian crews. Bristows have a proven track record(20 years SAR) with getting things done with the CAA, get them to right the book and present it to the CAA. I am sure the relevant management teams will have thought this through!!!!!!!!!!!! And presented a solution to the authorities!!!!!!!!!!