Have you tried contacting the 48th Highlanders and researching their Nominal Rolls and War Diaries?
You can research their names through the National Archives. The more information that you can provide them, the quicker their response. You should have their full names, their Service Numbers, ranks, Unit in which they served, dates of service, etc. All this information allows the National Archives to narrow their search and give you a better insight of their service records and awards.
Sometimes the Royal Canadian Legion can be of assistance.