Do regiments or battalions hold records of which company a soldier served with ,if so where would you obtain them
Some do, some do not; most, as far as I can see, do not. A soldiers' service record (Army) typically lists only the battalion, but may incidentally mention more. I discovered both my grandfather's platoon and company as he'd recorded it on a scrap of paperwork that turned up in a shoebox. In the first case, I'd contact the regimental museum or old soldiers' association (if one exists). Failing that, cross your fingers and consult the unit war diaries at Kew (the National Archives). If you are exceptionally lucky, there may be an expert on the unit you are researching present here: what unit are you talking about?
