Surely that first line should have "Farewell to London Town", or "Hullo to London Town" to make sense. Couuld suggest it's a variant on a version that did make sense.

Actually the heading of this thread with "Goodbye America, Hullo New York Town., which could make for a different kind of song. I've known people in England say they'd been to New York, and getting a response like "So you've never really been to America?"