Royal Artillery other-rank, post-1881.
The five-button 'frock' was the trefoil cuff embellishment was introduced in 1881.
The inverted chervons are Long Service & Good Conduct stripes, prior to 1881 they were worn on the opposite sleeve.
The forage cap he is wearing is referred to as a 'kilmarnock', but more commonly known as a "pillbox hat".
Isandlwana