My car is a Mini Cooper S R53.
I live in Japan, and if I can get the parts domestically, I don't have a problem, but if not, I often use Pelican Parts.
Pelican parts have a wide variety of products, and you can choose from genuine parts and aftermarket parts.
Shipping is fast, and it's a great help when I'm in trouble.
Also, the Pelican Parts website and YouTube explain how to replace parts, and I enjoy using them as a reference while maintaining my own car.
From my experience, I can recommend Pelican Parts.