I did a clear cache and all other files (from the beginning of time).
Whilst most people assume Opera has been done its, I went back in to check and selected ‘all cookies and site data’. It has cleared everything, except for an item from on web site. It wasn’t a ‘cookie’ but a ‘file system’ object. I am not sure of the difference between the two. I had to manually delete this item, from Opera.
Running Windows 10 Pro, running the latest edition of Opera.
Why didn’t it clear everything?