This appears to be a problem with our sso (single sign on) script. A fix is being prepared meanwhile there is a workaround in place and it should be possible to access the shopping cart once more.

Diolch for raising this here Kerrie. A ticket has been opened and we are looking into it now.

I am trying to order books from the book sale.  I have 3 in my cart, but each time I click on either the Proceed to Checkout or PayPal Check out buttons, it takes me back to my own home page.  I have tried Safari, Chrome and Firefox with the same result each time.  My popup window blocker is off.