My favorite place in New York is the Bop Shop in Rochester. Located in the Village Gate Square, 274 North Goodman Street.
They are open Monday through Saturday from 10 am to 6 pm, Thursday and Friday until 8 pm, and Sunday from 12 pm to 5 pm.
Reach them at (716) 271-3354.
I have not shopped in London in years, but was surprised at Harrods selection, especially for a department store. Might be worth a telephone call once in London.