Here's the hitch:

Upgraded to iOS6. Everything seemed fine. Then realised that only 1 of my many magazines are back on the newsstand. No problem, just go and install them again? BIG PROBLEM, I can see the magazines apps in the App Store, but their download buttons have been greyed out. And not only the ones I had but several other mags now as well.
I managed to find some of my mags to show the install button, but the button is also greyed out and I can only see "INSTA", instead of "INSTALL".
I have 3G, and only one of my magazines work perfectly now.

HELP