Philip
Something certainly did happen at Belfast in the Transvaal on 8 Jan., 1901. According to the SAFF Casualty list, the 2SLI suffered four killed or died of wounds, one Dangerously Wounded and prisoner (your man), two wounded and prisoner and seventeen prisoners unwounded.
According to Stirling's "Our Regiments", the 2SLI formed part of the Belfast garrison when it was attacked on the night of 7th January, 1901 and had about twenty casualties. Vol. V of the Times History (pages 123 -4) describes Botha's attack on Belfast on 7/1/1901; the SLI appear to have conducted themselves well at the Colliery post. Six other garrison posts were attacked more or less simultaneously and the Boer attack failed. Not, however, without severe fighting.
I do suggest you avail yourself of the availability of the Volumes of the Times History on the "Books" section of the site and discover the background and actuality of the attack on Belfast on 7/1/1901.
Best regards
IL.