Good luck to Starspeed but I think they will have the same issues as Sloane - providing a guaranteed service is next to impossible with the vagaries of the weather down there.
If you can offer a quick alternative solution - I was offered and took the option outbound of a Jet boat that came across from Tresco - then at least your customers get there but that relies on a decent sea state.
Until there are instrument approaches at each end with sub-100' minima I think there will continue to be delays and cancellations leading to unhappy customers.
Back to luckyrat's tunnel methinks......