Whee! A place to find hard-to-fit sizes that are functional, fashionable and unique, all with super friendly knowledgable staff.
I'm a new fan of IC London again. The new store (consolidates from East Boulevard and Ballantyne) is bright and fresh, and the selection seems bigger (or at least it's organized better so you can see the options).
Along with the white, nude and black basics, this new incarnation of ICL include some really fun colors and unique brands from France and specialty lines.
As someone who wears a unique size, you'll find it here, and get excellent service in getting fitted. The ladies here are much more attentive and knowledgeable about fitting than any department store, hands down. (Check your modesty at the door!)
Note: keep an eye out for coupons/check-in deals and sales. Some bras are over $100 and it's easy to spend big bu-ku here...but for something that fits perfectly and makes you feel great, it's totally worth it.