Do you know when John Gadney died? There's a John Gadney, of Oxford, cutler, recorded in 1740 and 1742. Or this might be his son. There was also a Thomas Gadney, of Oxford, tobacco pipemaker, recorded in 1711 and in 1697.https://heritagesearch.oxfordshire.gov.uk/search/advanced:combined/0_50/dateRange%3A1650-1750/score_desc/_%E2%B8%9EeyJ0IjpbeyJxdWVyeSI6IkdhZG5leSIsIm1vZGUiOiJhbGwiLCJmaWVsZHMiOlsiQUxMIl19XSwibSI6IkFORCIsImF0IjoiY29tYmluZWQiLCJkZiI6IjE2NTAiLCJkdCI6IjE3NTAifQ%3D%3Dhttps://www.british-history.ac.uk/commons-jrnl/vol11/pp754-756
Thomas the pipe maker was first recorded in 1697, so he might be a brother of your John Gadney. A bit earlier, in 1667, there was a Robert Gadney, of St Mary Magdalen, Oxford, taking an apprentice, thought it doesn't say in what trade. https://heritagesearch.oxfordshire.gov.uk/records/PAR211/5/A9/1-54