Crab
Surely the whole reason of the MOD giving up SAR is that the money they allocate to the service can be re-allocated to the front-line units who desperately need more equipment (in all 3 services)? Maybe it isn't, but if not why take SAR away? I suspect that the Treasury may have a different view to yours as well.
With regard to NVG, that clearance will have to come from the CAA and presumably the S-92 and AB139 will have NVG cockpits. However, the MCA is generally not responsible for overland SAR
AFAIK, so I do not know who will have that responsibility other than the Police. If the aircraft are to be NVG equipped for overland SAR, then will the MCA be paying extra? I, like you, do not know the answer. A good one to pose to those "in the know".
Like the military SAR units, MCA units have night flying training requirements to be carried out, just not so many hours as you have.