Unable to Enrol for iOS Developer Program

I'm currently trying to enrol on the iOS Dev Program and am getting as far as the final 'Purchase' part where you click on the 'add to cart' button to go to the Apple Store (UK in my case), but when I click on that I just get a 'The page you're looking for cannot be found' error from the Apple Store site. I've also tried searching in the Apple Store for the program, but no luck there either.

Looks like there's people on other forums experiencing similar issues - does anyone know what's up or if there's a way around this?