Hi Dave,
I don't know much about the WWI LF's but there's about a 25% chance you can get your GF's service record via the PRO, (only 25% of the WWI records survived the bombs of 1940).
Failing that, I'd suggest checking with the reqiment itself. They form part of the Queen's Division, based at Bassingbourn Barracks near Cambridge. A web search showed that they Regimental Museum is in Bury.
AndyG