This is the grave of Henry Burn.  As you can see, the top has broken off the headstone and obscures part of the inscription.  However we could see the name and part of the date of death.

We looked in the burials list (which is available to view inside the church) and found his entry.  It also gave a few other details.  It states Henry came to Savernake in 1814 and was living at Chisbury at the time of his death.  He was buried on 26th December 1861, aged 69, and the ceremony was performed by John D. Hodgson, Vicar of Great Bedwyn.