Looking for the Decendants of James Issac Davis of England About 1849

Issac James Davis was born about 1949 in West Lavington Wiltshire England. He became a ships carpenter and on a voyage to Australia on arrival he jumped ship. He built houses and haysheds in western NSW. He eventually married Jane Nell Spinks from Warialda NSW. Issac is my Great Grandfather and I need help with finding his decendants in England. Any help would be greatly appreciated.