There is almost inevitable pressure from the CAA for all public transport night flying to be pushed more and more in the direction of FULL IFR.
For "proper" Commercial Air Transport (i.e. carrying fare paying pax) the CAA have piled on additional requirements for UK ops - twin engine, autopilot (with heading and alt modes), significant extra restrictions for operations that are not full IFR etc. These have largely been as a result of knee-jerk reactions in response to a few notable accidents. Whether or not the new requirements would have made any difference to those accidents is a moot point - basically the CAA seem to use any significant accident as a reason for adding higher standards (or at least more regulations). There rarely seems to be regard to the cost of such requirements.
The police ops carried out under PAOCs in accordance with PAOMs have often not had to comply wth quite the same standards - basically they seem to lag behind the "proper" public transport case. I don't believe that the CAA have yet quite insisted upon autopilots for police night flying - but the next round of "improvements" is certainly moving in that general direction.
Ultimately, there is a move afoot to require police ops to comply with a modified JAR-OPS 3 standard - if/when this happens it may well be that autopilots will be required. In the mean time, it may be "economically sensible" or at least a good excuse to get new toys to look ahead .................
I wonder what the other ASUs who don't have autopilots on their helicopters are going to do??