Got it (subject to seeing the man's name and cross checking)
1st (British) Central African (or Africa) Rifles - slight variations of name are to be found. A predecessor regiment of the King's African Rifles. Officered by seconded British officers, in Mauritius in 1899, at least one other battalion as 2nd CAR is mentioned in a newspaper report of 1899. Many LG entries for officers seconded.
Hope we are allowed to se the name and date!!
MaxD