IIRC its more to do with the fact that in UK the Police/HEMS aircraft are certificated in the Public Transport Category, thus JAR OPS 3 applies in full.
Subject to confirmation from our European buddies, I think that they have a para-public category that exempts them from certain provisions of the regulations.
Regulations can change, but only slowly and painfully. I believe the Met Poliice intend to apply for a change to allow them to winch. Good for them.
There is a document that says that the Emergency Services are no longer to plan to use Military assets to assist in incidents. Thats why there is continuing work to expand the role of Police/HEMS in this country.