Just come across a death notice for Dr. Glanville in The West Sussex Journal from March 18 1879, so it certainly appears that his family were initially under the impression that he'd been killed at Isandlwana:
"On the 22nd Jan., killed at the battle of Isandula, in Zululand, Usher G. Doyle Glanville, M.R.C.S., L.R.C.P., dearly loved and only son of William G. Glanville, of Brighton, aged 34"
Regards,
Tim