helimutt,
You're absolutely right that the skills can be learned, but flying on operations with 2 observers (or doctors/paramedics/patients) is not the right place to be learning them. It almost certainly seems unfair, but military flying has so far been the best way to accumulate the time and experience required (night, low-level overland) for police and HEMS flying.
Police authorities and HEMS operators are there to provide a service to the paying public; flying training is not currently included in that service. However, if the industry continues to lose pilots with the required experience then the public may have to fund the extra training involved to bring operators like yourself up-to-speed. It'd be interesting to see how it'd be organised - perhaps an opportunity for a flying training operator to put an exploratory bid in to the Home Office
