Hi Stuart,
I have tried to re-produce this issue on my test portal and was unable to recreate the same behavior, plasae see the screenshot belowof your site taken using my DROID X. Can you login to our test site http://www7.smith-consulting.com/ and try to replicate the error. This will determine if the issue is with the latest version of the cart or an issue with your specific dnn portal/cart install. For login credentials, please send an email with a link to this post to support@smith-consulting.com.
Also since you are running an older version of DNN 5, you can create a fresh DNN 5.6+ sandbox on your desktop or laptop using the following link and install SmithCart so you can verify correct behavior which should isolate the issue as being in the Cart or your server/DNN portal setup.
https://www.smith-consulting.com/Foru...
Thanks,