I doubt it was the ASU flying it as they don't hire in relief aircraft or keep the crew current on a second type.
It was probably one of the mainly ex-Police machines that are out there and still in the hi-vis paint scheme and still have the camera turret fitted.
Vfr, if you let me know were in Lancs you are I will bring you a really noisy helicopter to compare. In fact I should offer the service to units and go and fly over complainants to educate them that the Police machine they are complaining about is one of the quietest on the market.
FNW