(1) a WILLIAM MOULD from Tisbury was a prisoner at Wilts County Prison, Fisherton, awaiting assize on 15 July 1817 (2) a HENRY MOULD from Chilmarkwas a witness to the case against William Mould on 15 July 1817.
I have no idea what the case against William Mould was - this can be found on Wilts Quarter Sessions records. My info is from a calendar of criminals and witnesses published by WFHS. But if your ancestors are from Tisbury and chilmark I'd reckon you're related to these two. Hope it's of some help