My son (16) is adamant that my father must have been SAS at some stage during his career as a soldier - and he may well prove to be right, yet. I know he was a bodyguard to someone very high up in the Army (a lovely man whose own career led to some fascinating stories, but more importantly, who always spoke to the then-toddler me as though my thoughts were the most important ones, to him, in the room), and I know he served as close protection to the Princess Royal during her younger years, following the attempt to abduct her (he couldn't stand her, apparently), but I couldn't really tell you where he was stationed, at all, prior to my birth, with any certainty. If we ask him (which we perhaps shouldn't do), he changes the subject, or tells one of a few vague-in-detail, yet rambling anecdote that doesn't tell you anything. My son says that he's come across a knife that only SAS of his grandfather's era were issued with, in his shed, before, when asked to pass one tool or another, but... I don't know. Apparently, when my son asked about it... my father took it off him and changed the subject. When, later on, my son went to show it to me - it had vanished. So there's obviously some things my father wants to keep to himself - and, y'know, that's his right.
I know that I may never know. Or, if I do, it won't be until my father's passed. We only discovered that my biological grandfather (maternal) was ex-SAS, after he'd passed. Had spent my entire life genuinely believing that he was ex-Para, that he'd had a fling with my grandmother (cheating on his wife with whom he had small children, so soldier cheats are not a "new thing" at all), who believed it was "true love", but knowing that he was a kind man, who never raised his voice, or lost his temper (not like the man my grandmother eventually married), and who cried whenever he got emotional (he sobbed over both me as a newborn, and then, 20 years later, over my oldest). Coincidentally, my father is also a kind, tactile, loving grandfather, so there may be something in it. When my biological grandfather passed, and it came out, all four of his children were shocked. I don't remember being shocked; simply very proud. IF my father turns out to be ex-SAS, then I hope my children feel the same pride in him.