Twiddle...It's alarmingly easy to combine casualty work and police work. It's rather more complex to combine HEMS and police work because HEMS is specifically funded by an external agency and is legislated under JARS as such, which is why police casevac has so many freedoms [night etc]...it's free, it's last option threat to life.
Handysnaks....it's not really a question of rural -v- urban being impractical, it's demonstrative of the fact that the emergency services would rather depend on separate funding [council tax -v- fundraising] than actually work together as integrated services.
Helinut...the rules aren't actually stupid, though they're not really clear. There are rules about carriage of public passengers and rules about medical passengers; the two sets of rules don't really make sense. As far as the in extremis cases go I am not aware of any cases where the individuals were threatened with prosecution. A CAA FOI phone call to query the facts [or more likely a CAA deafening silence] is not a threat of prosecution.