"About the object: A S Hartrick Celebratory scene. Lithograph. The characters portrayed are the remnants of the Charge of the Light Brigade saluting the King George V on the occasion of his Coronation on the Strand in June 1911. This was published in "The Daily Chronicle" the next day. See the description of this on page 219 of Hartrick's book "A Painter's Pilgrimage Through 50 years" (Cambridge University Press, 1950)."
[Source: https://www.barnebys.co.uk/auctions/lot/438419489/a-s-hartrick-celebratory-scene-lithograph-the-characters-portrayed/ (accessed 21.2.2017).]
It appears there are names identifying the men beneath, but illegible at this resolution. RM says it is based on a photograph which also names the men, so it should prove possible to identify at least some men.