My great grandfather fought in both world wars under the seaforth highlanders and then went on to be the gameskeeper at Balmoral Castle, What is the best way to research information about him and find out more about his past?
Ah, I've done this with my own great-grandfather. The process appears to be identical. You can apply for his military service records here.
Hi, hopefully someone else can add more, but FYI, there are some resources collected in our wiki,
https://www.reddit.com/r/AskHistorians/wiki/militaryrecords#wiki_united_kingdom
plus you may also get more tips from the family research gang in /r/Genealogy