Heli Austria operates a fleet of 5 902's for HEMS just fine.
Sure, now and again one needs a bit of work done, but which machine doesn't!
I have seen in the past, that generally the machines that are always needing repairs.........are the ones with a bad maintenance team behind them. (I am not saying that this is the case here as I have no idea about the UK ops)
The 902 is a great HEMS machine... Small, agile, NOTAR, pilot friendly design, and space for the Dr's in the back...