I think I can shed more light on this.
102 Arthur Frederick Wood is indeed 104 Charles Christopher Wood;s brother as per B.P.s staff diary.
Arthur is not on the Memorial Plaque because he survived the war and was discharged from service on 31 Oct. 1900.
Lieut. C.C. Wood is the not same person as Trooper 104 Charles Christopher Wood.
Lieut. Wood was killed on 10 Nov. 1900.
www.angloboerwar.com/books/92-maurice-hi...rom-the-orange-river