With respect Bertie, not sure that's the case.
For a start, unless I'm very much mistaken (apologies if I am), the Police helo would not have two IEC medics on board, casevac being only a secondary role for them.
Secondly, the dimensions of the small helos mean that attending to the casualty in flight can be very tricky, whatever the quantity and quality of medics on board - in stark contrast to the ease of casualty access in a Sea King or similar.
Thirdly, the one large helo could have, if need be, taken on an extra medic from those who attended by road. True, this would rob an ambulance of its paramedic for the time it took the helo to fly to Newcastle and back, but an ambulance is a less precious asset to tie up than a helicopter.
Besides, how much useful work could 4 medics have done on two casualties during what must have been a sub-10 minute flight to hospital?