I did make out the names Pitt and Chatham on this obelisk, but a lot of it was in Latin and I coudln't quite work out what it was about. Apparently it was created to honour William Pitt (the Elder), who I didn't know was Earl of Chatham, by Sir William Draper, who was living in nearby Manilla Hall. When Manilla Hall was demolished and replaced by Manilla Road, the obelisk was moved here.
GPS Coordinates:
51.45693, -2.62097
Location: Clifton Down