Found - a snapshot of W.E. Gladstone (1809 - 1898) the original 'Grand Old Man' (G.O.M.) at his country seat Hawarden Castle. He was Prime Minister 4 times, resigning finally at the age of 84. At the time of this shot (1877) he was out of office. Written on the back of the photo (found in a book by W.N.P. Barbellion) is 'Gladstone Centenary, December 29th 1909' (crossed out). Unique photo of late Rt. Hon. W.E. Gladstone taken at Hawarden in 1877.' Under this is a stamp 'E.J. Lavell 115 Bedford Hill, Balham S.W.' This is presumably the shop that processed the photo. An online image search reveals another fuller shot (on flickr) from the same session revealing that the implement to his right is an axe and showing his straw boater on the ground beside him. There is a note stating that he was relaxing after chopping wood.
I was talking to a dealer in Portobello Rd on Saturday and she told me that she owned a copy of this same photograph of Mr Gladstone