There is currently a problem with our shopping cart – it will only accept one item at a time!
If you just want one item you can add it to the cart and checkout as normal.
For more than one item, please checkout one at a time (it’s a pain, sorry) and we will refund any excess shipping cost that the cart charges when we process your orders. We are investigating the cause as a matter of urgency with the shopping cart developers.
UPDATE (September): We appear to have fixed it now. It was caused by an interaction between the shopping cart and the cookie control plugins that both developers denied could happen!