onClick="document.getElementById('next').disabled = false"
On the next screen it confirms the details and if need be offers the option to go back
Unfortunately, the Submit button is re-set to disable, even though the Radio button is already selected.
The other issue is that sometimes when going backwards then re-submitting, some of the changes aren't carried over, if you go back and hit submit again however it's fine. My testing on this issue initially showed it was just a timing thing.
At present the biggest issue is the onback function and avoiding disabling the Submit/Next button.
If anyone can help with either or both it'd be much appreciated.