Hi Nick,
Richard actually died in 1760. According to the image of the Westborough with Dry Doddington Parish register, available on FindMyPast, in the record for 1760 "Richard [the son of Wm] Pickworth of Westb. buried January 8th".
Note that the vast majority of Lincolnshire parish registers have images on FindMyPast.
I also noted, a little further down the register, still under 1760, that " Richard, the son of Eleanor Pickworth, Widow of Westb., baptized July the 21st.".