@timt55 . Your incoming port 995 uses SSL/TLS security. What is security on your incoming connection?
If you have the same setting for sending security, you should use port 465. (Port 587 uses STARTTLS or NONE.)
@timt55 . Best to ring Apple support. Your receive connection works so don't change it. You want the send side to work in basic mode, then change to use encryption.
With the proper settings, mail will work on wifi and mobile data.
Adjust your iPad to match your phone.
@timt55 . The phone is not broken, just the settings are wrong. TPG will only refer you to this article. It has the settings for TPG mail server and description for iPhone. You won't be adding an account, just checking that your settings match what's in the article.
When you have it working in basic mode, consider using encryption as the next step.