Under the Civil Continguencies Act of 2004, the SAR Force were the odd ones out as the only military asset acting as a Category 1 Responder. Seeing, as all other emergency services are provided by civvies then I see no reason why SAR shouldn't follow - fire engines, police, ambulances all have primacy in the UK on the MOD estate or of it.
As for using bright yellow helicopters in times of war collecting downed aircrew - now that really has made me chuckle...
Well done SAR-boys. You have done a 1st class job over the years. Now it is time to bow out gracefully...
LJ