More specifically, is there any way of finding out what weapon he would have been issued? I will hopefully be buying an Enfield rifle next week, and I'd like to get the type that he would have had. I have seen photographs of other battalions in his regiment with both Long Lee Enfields and SMLEs, but I haven't (yet) found one of his battalion.
For reference he was in the 8th Battalion, The Border Regiment, based in Carlisle, Cumbria (UK).
For records, I would start here:
https://www.gov.uk/get-copy-military-service-records/overview
Apologies but I do not have the knowledge to answer your more specific point.
Hello there! As your question is related to looking for identification/information regarding military personnel, our Guide on Military Identification may be of use to you. It provides a number of different resources, including how to request service records from a number of national agencies around the world, as well as graphical aids to assist in deciphering rank, unit, and other forms of badges or insignia. While the users here may still be able to lend you more assistance, hopefully this will provide a good place to start!