Ob: Which London Underground or DLR station name has the most letters
in common with "checkout clerk"?

I may as well answer for the record. The question was just off the cuff,
so it's not surprising that the answer turns out to be a tie. There are
4 stations each having 8 letters in common with the phrase: {Finchley,
Hendon, Hounslow} Central, and Gloucester Road.
--
Mark Brader | "How do you know I'm mad?" said Alice.
Toronto | "You must be," said the Cat, "or you wouldn't have
| come here. This is, after all, a Bridge Club."
| -- Ray Lee (after Lewis Carroll)