The cut of the uniform strongly suggests the picture dates from the late 1850's to the early 1870's, which would be about right for a young man born in 1843. The style of uniform also suggests a rifleman (as opposed to line infantry), but besides the regulars there were numerous volunteer rifle units in Britain during this period. It is tricky trying to judge color from old black-and-white photographs, but it seems to me a little light for the dark green used by the regular riflemen. Gray uniforms were worn by some of the volunteers. Don't forget to consider the possibility that the photograph was taken in Australia, which had its own units.