Thanks Jason
I couldn't locate the issue, so ran the checkout wizard again and they are now working again.
I also solve why I couldn't select my templates in the wizard - turns out that, as I was working directly from my network/NAS drive, eCart couldn't see them - even though the doc prefs were correct. As soon as I moved all the files on to may Mac's local drive - it was fine. Don't know if this is something you have come across before?
Thanks
Steve