Do any other New Yorkers remember this shop, which was--back in the
day--about the only way to get British titles here in the U.S.?

When I first encountered them, they were on or near Lexington Avenue,
I think, in the East 50s. Their prices seemed to me to be on the steep
side, but I guess it's always been more expensive to ship books from
the UK to the US than vice versa. Later, they moved up to the 70s,
which is hardly prime bookstore real estate, and from there they faded
away.

Now, of course, one can easily order from Foyle's online, or Book
Depository, but I still wish I'd gotten more of the things I saw
there...