Nit Picking I know, but I'm sure that the Scillies machines are S-61s, which although bearing similarities to the Sea King, is a different aircraft.
I would imagine that the original Mk3 Sea Kings (circa 1978/79) must be up around 15000 hours by now - I remember when they went through 10000 some 10 years ago. I have no idea what the RN cabs have - traditionally they had fewer hours than the RAF ones, but with recent ops in the 'Stan, they may have increased significantly.
...perhaps someone with access to the 700 can shed some light?