I note today from the local press that BIH are going to permanently relocate the S-61 service from Penzance to Newquay from October. They will continue to operate out of their Pz base until then and had been looking around for a new site in West Cornwall.
Routes to St. Mary's and Tresco will presumably cost rather more than the present £190 return in view of the additional mileage but my assumption would be that they will save on the significant infrastructure costs associated with a new base in West Cornwall where some might say the nimbies have been out in force just recently.
I imagine Scillonians will not be best pleased with this development.