Donop continued playing cricket while serving with the Royal Engineers: in one match, against the Harlequins at Chatham in June 1884 he scored 91 runs out of his side's total of 224.
[7] In September 1884, as a member of the Royal Engineers' 8th Railway Corps Company, he was posted to Egypt to take part in the Nile Expedition.
While in Sudan, his company constructed 87.5 miles (140.8 km) of railway track, from Sarras to Akasha, to facilitate the transport of provisions and stores to and from the fighting front.
[13] He continued to play cricket at club level and, in January 1890, he made two appearances for G. F. Vernon's XI in matches against local sides at the Gymkhana Ground, Bombay.
He formally resigned from the Royal Engineers in November 1902,[15] while working for the Board, was promoted to Chief Inspecting Officer in July 1913 and held that position until his retirement in 1916.
[19] As well as playing cricket, Donop was soon selected to represent his regiment at football,[20] and was in the Royal Engineers' team which reached the 1874 FA Cup Final.
[21] The following year, the Engineers defeated Oxford University in the semi-final to set up a second consecutive appearance in the final, this time against the Old Etonians.
[30] His youngest brother Stanley served in the Royal Artillery, achieved public recognition when he led a column during the Second Boer War, served as Master-General of the Ordnance (the fourth member of the Army Board) and as Colonel Commandant of the Royal Regiment of Artillery, and ended his career as Major-General Sir Stanley Brenton von Donop KCB KCMG.