I know this may wind some up - it's just opinion!
I would imagine there are many who would also baulk at having a civvy Observer in the aircraft, but bring a few on, I say. Police flying is NOT rocket science that absolutely requires every Observer to be a Police Officer. It is, however, fairly scientific and requires a fast brain to multi-task effectively and be a good Police Obs.
Bringing in (just) a couple of ex-military crewmen (even Crabs) to a unit, for instance, (who have many years of aviation experience and therefore already have the third dimension very much in hand) would require very little training to learn the Police way of doing things etc. Searching for suspects, directing officers on the ground, following targets does
NOT require Police experience - it requires a brain capable of multi-tasking and logical thought processes. In addition, if they're on a contract similar to (contract) pilots, they would feel it imperative to keep their skills sharp if they wished to stay in the job, as they wouldn't have the cushion of the rest of the force to fall back on if they weren't cutting the mustard!
The training of new (previously used to two dimensions only) Police Officers to understand the complexities of the third dimension, and then add the job of listening & responding to up to 7 different audio inputs whilst directing people on the ground is, IHMO, a significantly greater task than using people who have the third dimension in their blood - hence the use of military pilots often finds them able to assist the Observers as second nature, rather than only by request.
There are already a couple of very capable civvies at Suffolk - the argument
about having to have powers of arrest is so weak, given the frequency of requirement, that it sounds more like desperate justification!
As for Crabs -
