They may be getting a new order in. They take them off the site when they're out of stock, and add them back when they get in stock. Could try posting up on the polished bliss section of dw and see what Rich says :shrug:
I believe Clark mentioned when they out of stock they won't be re-ordering choosing to go with the Gloss-It pads instead. I believe Ken (911Fanatic) on here stocks the Gloss-It range, maybe consider them seeing as they are more easily available to you guys over in the US/Canada and his service is top notch :thumb:
I heard Polished Bliss will no longer be stocking 3M UK pads. i4detailing and Autobrite Direct carry them.