A W.H. Clark dies in Bethnal Green District 1935 aged 87. This would give a birth circa 1848.
I have found a William Clark b.1851 st Johns London, attested 25 Nov 1869 age 18, to 2nd D Gds 26 Nov 1869, to 1st KDG 18 Feb 1879 to SA 28 Feb 1879 to 20 Oct 1881 discharged this date at Pietermaritzberg reason invalided, served ZW and 1st Boer War at Laings Nek Gunshot Wound to Arm. He served just under 12 yrs.
Not 100% that these are one in the same??.