In August 1828 Wynne and his younger brother William attended a Sligo Protestant dinner at which toasts were drunk to the former Tory lord chancellor Eldon and their father, patron of the pocket borough and its Member, who they declared had ‘never deserted the Protestant cause’ and ‘never will’.
At the 1832 general election he stood unsuccessfully as a Conservative for Sligo, where the Reform Act had weakened his family’s control. In 1843 he was appointed a member of the commission of inquiry into Irish land tenure, in which he took an ‘active and prominent’ part. He served as under-secretary to the Irish viceroy Lord Eglington in the first Derby administration of 1852 and sat again for Sligo as a Conservative, 1856-60. Wynne, who was ‘well versed in Irish antiquarian knowledge’ and an ‘indefatigable field botanist’, died at the palace of the archbishop of Tuam, where he had gone on a visit, in June 1865. He was succeeded by his eldest son Owen (1843-1910).
