Loose Cyclic, with the experience that you list, I can't see that you should have any trouble getting a Police/Hems job. I'm not quite sure what the experience with emergency services is that some posters allude to. The UK airspace is not that complicated; just don't cross a blue line on the map without talking to someone!!
The minimum requirements for Police flying are: 1500hrs rotary with 500 PIC overland(with a significant proportion of low flying). A minimum of 50hrs at night with 20 hrs PIC.
As said, these are the minimum, and there are one or two units who look for higher.
Oh yes, if anyone's wandering about the lack of posting from Thomas Coupling lately, his unit's been banned from using the internet apart from police business.

Hope they don't do that here!