Based on what we do at work, i.e. the Civil Service - and the way my daughters were told to do it when doing their Uni dissertations and theses - if you are quoting the exact words as they appear on the card, then they should be italicised within single quote marks - if you wish, you may follow this up with an 'explanation' in brackets so you might put ... 'Cam'n Hdrs Depot' (Cameron Highlanders' Depot). You will note, I've put the apostrophe after the word Highlanders in the explanation - this is because the regiment is known as Highlanders, is therefore already a plural, so the possessive goes after the final letter.
Thereafter, it's perfectly acceptable to use words such as Cameron Highlanders, Depot, Corps, Regiment or any other words which appear on the card without quote marks - just because you are repeating words which appear, does not mean you have to automatically put them within quote marks.