Another relevancy item: A pilot with no military experience will probably not (at least if he has abided by the UK ANO) have been used to operating to the lower weather limits that the Police role requires.
This is especially true by night (when things often get busier).
Police Air Support Units are run on a very tight budget which comes out of the same public purse as everything else the force requires. There is little scope for training up a pilot who needs it. While the marketplace can provide enough pilots qualified iaw the present requirements, nothing will change.
Supply and demand. Market forces. Usual story, just like any other operation.