Carnaby Street
From Tardis Wiki, the free Doctor Who reference
When Polly emerged from what was likely her first trip into the TARDIS wardrobe, she was impressed by the First Doctor's selection of clothes, and wondered if he had "gone shopping on Carnaby Street". (TV: The Tenth Planet)
Behind the scenes
The logical interference from the line is that Carnaby Street was famous for its fashion — which it is.