PM to me with your email address - I might be able to help - I have a similar - got me going about those - I do have the book by Ron Bester, as well as the three volumes by David C. George - probably about the best references to ID the thing. Will take multiple pictures of really "silly" details, but is worth to find out what you have, I think ...
Just FYI - there were two "Boer Republics" - "OVS" - Orange Vrei Stat - Orange Free State; and ZAR - Zud Africa Republik - South Africa Republic
From the references, is a bit odd to have a straight handle bolt on a long rifle - at least a couple reasons why that might be an issue. Also, all the references explain British, Canadian and Australian handling of captured arms from Boers - will be a bit unexpected to have a bolt with a matching number to the receiver. We can discuss.