hi, in responce to the bee on scillies thread i posted a few days ago, i had also emailed the isles of scilly wildlife trust. i have had a reply today.
(quote from email)--The bee you have photographed is unique to Scilly and is known as the Scilly bee, Bombus muscorum scyllonrus. It is an endemic subspecies of the Moss carder bee. It can be seen feeding on heather and Bird's-foot trefoil around the islands especially on St Agnes.
my particular bee was photographed on st helens, one of the uninhabited islands. many thanks for your responces.