Hi Andy, welcome aboard!
I've found three pages from the medal rolls that list him. Here are the details:
6078 Driver C.F.Moseley, Royal Battery, Royal Horse Artillery is listed on the QSA roll under Army Order 1 April 1901, WO 100/139, pg 168, Royal Battery, Royal Horse Artillery dated 20 June 1901, Bloemfontein as QSA with Paardeberg, Johannesburg, Diamond Hill, Wittebergen, & Relief of Kimberley clasps. Then there is a document in WO 100/137 noting that he was issued one medal (QSA) and five clasps on 28-12-1901. And then Army Order 232, 1 October 1902, WO 100/306, pg 68 (undated) shows KSA with South Africa 1901 & 1902 clasps.
I had a look on Ancestry and Find My Past to see if I could see any service papers but nothing seemed to come up but it my be worth it to double check both these websites.
Diaries are always of great interest. I'm sure a great many members of the forum would be most appreciative of any extracts from the diary that you may want to share.
Cheers,
Mark