I have just spotted this sermon, published in 1708, by the rector of Therfield, on sale on ebay (end of auction just before midday on 30th October). If you are interested in Thomas Sherlock or the village you might consider bidding. I have added details of Thomas Sherlock, and his father William Sherlock, both of whom were Rectors of Therfield, on the page for St Mary's Church, Therfield.
