ppheli,
You asked about the £1700 per hour.
Looking at the overheads for a 365, 24/7 operation with 2 crew at all times you would need to fly something like 450-500 hours a year. That figure wouldn't take into account the cost of buying the aircraft or any interest on a mortgage.
I think the proposed operation isn't a viable option in a S76 as the running costs are too high.
FNW