The memorial you mention from St Vincent's Church has the following inscription:
IN MEMORY OF SIX BRETHREN OF THE GUILD OF THE HOLY STANDARD WHO FELL IN BATTLE AT ISANDHLWANA 22 AND 23 JANUARY 1879
CAPTAIN F.B. RUSSELL RA
PRIVATES J. FAIRCLOTH, J. HOLLAND, N. KEMPSHALL, W. THEOBALD AND G. TODD 24TH REGIMENT S.W.B.
MAY THEY REST IN PEACE
Unfortunately the plaque seems to have been removed from the church some years ago, and I'm led to believe that it turned up at a militaria fair in the UK in 2019.