This is an interesting  and rare maker's mark, particularly as both pairs of tongs appear to have been overstruck. There are quite a number of makers with the mark "TP" recorded but most are without a pellet. I have plumped for Thomas Pepper I as his mark has a pellet and was registered before these tongs were made. Thomas Pitts I is a vague possibility but Heal only records him working up to 1793, and he was a plate-worker.

Thomas Pepper I recorded his first mark as a small-worker in 1767 and another in 1772. Heal records Thomas Pepper as a "Goldsmith and enameller" between 1790 and 1796. Thomas Pepper II recorded his first mark as a plate-worker in 1809. The dates therefore don't quite match up unless Thomas Pepper I was working between at least 1767 and 1796. Given that both of these pairs of tongs are overstruck and therefore not likely to have been made in his workshops, I think Thomas Pepper I is definitely a contender.