Basically, I'm willing to acept that if the airport is within the boundary, adjacent to it , or at a stretch within 15 minutes by reasonably priced surface transport, then it's fair to call it after the nearest large settlement, but only after one place.
That's Tokyo Narita buggered then. Northwest and Air Canada adverised Glasgow (Prestwick) and London (Gatwick) all through the 1980s so it's not a Ryanair invention. Prestwick serves Glasgow, always has done I'm afraid and has been sold as such to the world for over thirty years. BA may even have done that but that predates me alas. I find PIK into Glasgow is less painful than Heathrow into town, love the Tube as I do!
Though I agree London Southend is rather pushing it....