The recently launched menswear website Mr. Porter now stocks exclusive brands that are not easily available here such as R13, Boglioli and Jean Machine.
The latter is especially noteworthy, being newly released and relatively affordable (shirts from $200). The classic denim jackets (from $300) are also great and will remain a staple in your wardrobe for a long time.
Delivery’s a swift two to three days though you’ll probably want to pay a little bit more for express shipping.