Crab: Small correction there - one can work very comfortably on a patient in an Ec135 (and I would surmise a 902 also). It's not a bolkow 105 you know! There are (in my experience as a HEMS driver (also)) no restrictions working on casualties en route (including defib in an a/c).
The current crop of 'new' generation light helicopters (<3175Kg) in the emergency services configuration would struggle to fit a winch. They take up an inordinate amount of vital payload...something that should be reserved for the primary role of the police/AA Unit.
They aren't cheap (£150,000).
Both of these are surmountable though given an incentive.
What isn't surmountable is the legislation. Jar Ops 3 (HEMS and AA Ops) and CAA (Police Ops) won't allow commercial operations to train in an aircraft that can't sustain SSE in the hover during winching trng...end of story.
The EC145 hasn't a hope in hell of SSE in the hover!!!
The 109S could/might just do it at the right WAT.
But there is only one emergency services 109 in the country.
Ways round it: Fly outside the national rules - Paramilitary rules.
And that my friends is a whole new can of worms
The Met were looking at responding to the terrorist threat primarily, rather than winching stranded fishermen from the Thames!!! Even this is a no go from the CAA (In their current 'commercial' configuration).
Anyway there is insufficient call for coastal SAR from the Police / AA. Thats why we have the coastguard and the bloody RAF
