Thank you Ray.
What has happened to my background? I understand that what I'm looking at, whilst it says checkout.php in the address bar is actually either confirm.php or confirm_cart.php but shouldn't they pick up on the CSS from checkout.php. They are displaying other formatting that's in the CSS, like text formatting.
It's not saving the co-ordinates correctly. It only appears to be saving the x co-ordinate. Might that be because we have them separated with an : character?