Rob - sadly neither of your suggestions work for me here in Wales. Does his service record give personal details and confirm Captain Holtby was Alfred Charles Holtby born 1862/63 in North Cotes/Coates in Lincolnshire. He can be found on the 1939 Register showing he was born on Boxing Day 1862 and at the age of 76 was an Air Raid Warden.
Despite being the son of a prosperous farmer, farming was not for him (probably because he had an elder brother), and after attending Spilsby Grammar School he attended college and trained as an electrical engineer.and then in 1895 emigrated to SA and worked in the gold fields. I think he returned to the UK permanently in the early 1930's. In the British newspapers he gets a number of mentions before and after his time in SA but only one while he is in SA. In 1918 he is mentioned in the annual reports of the "Consolidated Gold Fields" where he receives praise for the work he did in establishing "The Central Buying Department of the Chamber of Mines" which lead to significant savings by the standardisation of materials etc.
Regards, David.
