In message , Phil Richards
writes

First question: Roughly when did Lower Regent Street get renamed into
Regent Street?

I think it's only ever been a colloquial name, albeit widely used (the
Royal Mail database records the "Lower Regent Street Post Office" as
being at 11, Regent Street, for instance!).

Second Question: Is it simply worth firing off a complaint to LUL to
ask why the street exit signs haven't been changed?

Why? There are all sorts of signs that refine the exact location of an
exit (e.g. from Green Park ... "Piccadilly North"). There is no
expectation that a road is named Piccadilly North.
--
Paul Terry