The “unknown” officer in the front row on the right, is Fitzhardinge Robert Bayfield Liebenrood. He is wearing a star on his collar indicating his rank as an Ensign.
Liebenrood’s commission was obtained by purchase on 1st October 1870.
With the changes made in the ranking system in 1872, Liebenrood was promoted to the rank of Lieutenant on 16th July 1872. The photograph therefore pre-dates that date.
On 12th July 1873 Liebenrood retired his commission.
I started trying to research F. R. B. Liebenrood, when Kate posted the information about George Liebenrood of the 58th.
What I discovered was that he contributed articles to The Engineer magazine. He also played cricket for Essex as a Gentleman. I believe that his son Fitzhardinge Hancock Liebenrood played for the M.C.C. and England, changing his name in 1921 to Fitzhardinge Hancock.