Jayne,
Just to let you know the 2nd photograph is that of a volunteer, rather than a regular army, senior N.C.O. Given the 'Drum' above the inverted chervons I think he might be a Drum-Major, rather than a RQMS as suggested by David. If the photograph pre-dates 1898 then he would be in the Medical Staff Corps, rather than the R.A.M.C.
Isandlwana