Have just found A&W Root Beer and Diet A&W in London, at a fantastic diner called JACKS in Clapham Junction, 2 mins walk from the train station, address is 252 Lavender Hill, SW11. Not only do they sell A&W, but also genuine American milkshakes, mozzarella sticks (I've never found these in London before), the BEST onion rings...shall I go on? Oh, yes, burgers! Try them! V cool atmostphere too...