Dealing with typing archaic letters to get a specific date/time pattern is just wrong. And a link to a PHP manual is not the answer... unless you're a programmer.

Some options - there should be a list of common examples on that page (e.g. how do I add am/pm) - Replace the PHP.net tutorial link with one on bdcms.org that explains it better - get away from having the user deal with PHP stuff. Provide some kind of drag and drop or GUI to help. Not sure what at the moment.
This always takes me time to figure this out.
Recent comments
Thank you, I did clear the cache, but have now realised the hosting platform had its cache service enable.
Maintenance mode not working
That's usually down to the cache. The cached version will carry on showing unless you clear caches. However, at some point the cache will expire or someone will access a non-cached page and then...
Maintenance mode not working
I think in the meanwhile I'll have to just stick to legacy version Not for long, it seems. A fix is already underway. ๐
leaflet widget stopped working