It’s all sorted now.
To anyone else who ever reads this Line 14 looks like it’s the start of the body of the email. It isn’t. It appears to be completely irrelevant to what the recipient receives.
Start your editing at Line 43 which is the real start of the message.
When you save, it does apply immediately.
(I wanted to test the template edit and was fooled by Line 14 being ostensibly the first line of the email)
Now it’s sorted courtesy of 3CX support I’d like to pass on my thanks and also the following for others.
Tip.
Copy the whole html of the template into a new Notepad++ window and save to your desktop or wherever as welcome.html
Open welcome.html in your browser.
Edit in Notepad++ and save as you go and review by refreshing your browser window.
When done copy the whole html from Notepad++ back to the 3CX template.
Some knowledge of html is required.
Notepad++ is a Windows app that frankly is a must have.