Where are you? I live in London, and went to the Birks shop in Covent Garden. To find out, I called their head office, and told them I was in central London, and they gave me a few places to try. So, give them a call, on 0171-603 2644.
I bought some sandals which were on sale, fortunately! But UNfortunately, they didn't have any closed shoes in my size on sale. That's ok, I'll try again next sale time. Meanwhile, I am in foot-heaven, clumping around in the sandals most of the time, and I also bought some blue inserts to go in other shoes, and they help a lot.