Ah yes. Bookbox has solved it. Robert Thomas was Assistant Overseer in the 1851 census.
Many thanks, Shaun and Bookbox.
Given Robert's bureaucratic/titular role as Parish Clerk, I think an ancilliary bureaucratic/titular role, also appointed by the parish, is more likely. Additionally, the enumerator has apparently been impressed by the importance of these roles in this tiny village and capitalised both titles.
AI corroborates Bookbox: "Under the Old Poor Law, an assistant overseer was ...appointed by a parish to assist the overseers of the poor with the administration of relief to the impoverished. These individuals were often responsible for tasks like collecting the poor rate, maintaining records, and managing outdoor relief ... which could include money, food, clothing, or housing in an alms house."
However, AI is not clear as to whether it was a paid or unpaid position. My guess is that Robert was probably paid as his parish combined the roles.
Many thanks
Best wishes
John