During the old days of Empire chaps needed to spend long periods in far flung corners and so needed tailors who, while not being exactly Savile Row, could at least make a uniform and a blazer that would do him until a chap got back to Blighty. Since the Empire turned into the Commonwealth and most of the chaps came home these tailors all claim to have been Tailors to Her Majesties Armed Forces.
One of the Chaps patronised just such a tailor and wasn't wholly disappointed with the results. That they do the fittings in your hotel room, finish the suit in four days and charge less than dinner for four at Le Gav was also a pleasant surprise.
When wearing a suit made overseas it is not necessary to point this out. A Gentleman can tell from ten paces and wouldn't refer to the fact, assuming merely that a chap'd served abroad.