I have had success finding out where a regiment served and the exact dates by contacting the regiment's library/archive/museum. Use a search engine like Google.com to find out where the regimental headquarters are. In my case (Seaforth Highlanders) I found a published history of the regiment which was only available for purchase from their museum. It describes the battles they were in during the Boer war and the medals that were awarded. Unfortunately only gave the names of those who won the VC. Good Luck, Gail Lynch