I just wanted to post back on here as I managed to upgrade from 7.13.x to 7.14.1 finally. I saw another forum thread (sorry can’t remember which one) suggesting running the update with PHP 7.4 as the problem I encountered is only an issue with PHP 8+. I rolled back to PH 7.4 and the update ran perfectly first time using the 7.14.1 Upgrade from 7.13.x dated 3rd October. I then moved back to PHP 8.0 once it was done.
I’m going to hold off on going to v8 for now, but at least 7.14.1 is a step forward.
Hope this helps somebody else.