Aha, now I see what the problem is. And I can help others get at some more of the papers. Desy, you are correct the papers are still there, but the links from the page above which offers Higher, Resources, and Standard is broken: and this is how most people would navigate to what they want. However, if one adds Higher, Resources or Standard to the end of the URL then this takes you to the right page.
The same kind of trick seems to work for other subjects too, and for individual papers where the link does nothing. Hopefully this will help people get what they need.