Let me see, I have been thinking about this proposition and query. Rockall is as I recall about 260 miles offshore from the WNW corner of Ireland. At first I was thinking block hours on a Chinook or an S53G or somesuch machine then I wondered who would already have a ship with a helipad in the vicinity with access to a helicopter to boot and it turns out that the UK, Scotland and Ireland already have such equipment in everyday use off their shores.
Why not give the Commissions of irish Lights a bell, they have a ship (Granuaile) with a heli-pad on the front deck and access to both bolkow helicopters equipped for offshore and also more recentyl an EC135T.2+ also equipped for offshore operations and in tandem with a ship which carries fuel for it.
The other advantage is the ship is already in the Irish region hence there would be no position trips to fork out for. Just an eurika moment I had earlier whilst sittign in my shed. At least they could advise being pros on those types of operations servicing the soem 15 rock lighthouses off the Irish Shores?