Pastry for the Crackers

I would love to make the recipes in Delia's Happy Christmas book that use Feuille de Brick pastry. Unfortunately I can't find it anywhere. I have tried Waitrose, Ocado (as advised by Delia in a newspaper article) & M&S, all to no avail. Can you advise where I can purchase this pastry? I live in London.
Kind regards
Karen Morley