Hoiststop - our winchmen are very well trained in Emergency Medicine - they are fully paramedic qualified. There is no point taking an ER doctor to a scene when the casualty is in a precarious position (cliff, deck, in the water etc) when they need to be rescued first and treated second. Hospital staff are often a liability in these situations because they are so far out of their comfort zone they become another casualty.
More often than not, you are within 30 mins of a hospital in the UK and the most significant delay getting the casualty to definitive care is usually waiting for the ambulance at the HLS.
So, although I take your points, I really don't think that we 'lag' behind others in the UK SAR world and trying to combine SAR and HEMS just wouldn't work, they are different jobs, albeit with some significant overlap on occasions.
It would be interesting to know how others would have dealt with the 29 stone (406lbs or 184 kg) patient my boss was faced with the other week. Including the trolley he was on, the combined weight was an estimated 500lbs (227kgs) and it took 10 people to lift him into the aircraft! Try doing that in a HEMS helicopter!!
They had to borrow sheets of plywood from the building site next door use spread the load of the 4 small trolley wheels on the cabin floor!