Brad.
Your Gt Grandfather will have served with the 3rd Bn Manchester Regiment. They served in St Helena, as Mack suggests - guarding Boer prisoners of war, then on to South Africa where they remained until instructions were received for disbandment of the battalion. They returned to England in November 1906 where disbandment was completed by early December 1906.
Those soldiers with time still to serve were then posted on the either the 1st or 2nd Battalions.