I believe that it was the 2nd Battalion of the Buffs who were in the Boer war and it was to them that the Volunteer Battalions provided an attached company to.
http://queensregimentalassociation.o...0Regiment).pdf
The 1st Bn were in India.
There was also the 3rd Battalion (former militia) who were in SA in 1900 before being sent to St Helena to guard prisoners.
There was not a 4th Battalion until 1908. It was this battalion which had the scarce 4th battalion badge although it is such a scarce badge that I do wonder whether it was on general issue in any numbers.
Alan