Hi Crab
You have to go back into slightly ancient history to understand where the HEMS experience requirement comes from. Under JAR, there was a minimum of 1000 hours P1 set for command of a HEMS helicopter; however, there were some operators conducting multi-pilot HEMS and someone thought to ask how a HEMS co-pilot could ever gain 1000 hours of P1 in that role. The fairly sensible decision was made that a co-pilot with 1000 hours of HEMS experience will have a good chance of passing a HEMS command course. It is the 500 hours operating a helicopter in a similar role that is pertinent to the SAR pilot, the HEMS co-pilot experience is for HEMS co-pilots.
Also:
It is a nonsense since so much of HEMS is covered in everyday SAROps - the only real difference is not having to comply with PC1 profiles.
is a bit of a red herring. Not only is there no requirement to operate in PC1 at a HEMS operating site, it is impossible to do so unless your HEMS operating site happens to be a pre-surveyed landing site, a surveyed heliport or an airfield. PC1, by definition, requires a known obstacle environment so an un-surveyed HEMS landing site can only ever be PC2 at best.
Cheers
TeeS