The 61st Foot were in India in 1851 (having arrived in 1845) not returning home until 1860. During their time in India they fought in both the Second Anglo-Sikh War of 1848-49 and the Indian Mutiny of 1857-58. This all fits in nicely with your research so far.
"Don't talk to me about atrocities in war; all war is an atrocity." - Lord Kitchener