Hi Barry, yes the Lloyd Webbers do have Devon ancestry! From memory I think they are descended from a Lewis Southcombe's family from Swimbridge. He was born a few miles away in Rose Ash where there are a multitude of Southcomb(e) names in the registers. The Southcomb family who dropped the 'e' were rectors of Rose Ash for over 250 years.
Another branch of this family came from the parishes of North Molton and East Buckland, which is where I think your ancestors fit in. My 3 x great grandmother was Eliza Southcombe who was from Swimbridge; she married a William Harding and they gave a number of their children, including my 2 x great grandfather William, her maiden name as their middle name. There was a really good article in one of the Devon Family Historians, I think about 4 or 5 years ago, and these are on the Members' Area.