I once Googled it.  There are places that sell it, but it's about £7.00 postage!  There is a place in the West End but the minimum tube fare is about £4.00 each way.  Like I said, there was a time when off-licences used to sell a variety of drinks by single cans or bottle.  Ok, so it cost a bit more in the long run, but I don't fancy buying four-packs if I just want the occasional drink.  I like Newcastle Brown occasionally, and used to drink proper barley wine (Gold Label) but I'm not a regular drinker.  I could go months without one.  I live directly opposite a pub, and the only time I ventured in there was when somebody stood me a meal one Christmas.   You'll find that most older people prefer to have a quiet drink at home.