It's a shame you did not take a screenshot of the hang.

It was the 503 Service Unavailable (_maintenance.html or umaintenance.html) I image.
I just replaced the file ending to recreate the issue and now deleted the files.

No, not that page. The page where the install hung. because I wanted to exactly precisely where it hung based on what was displayed on screen and what was not.

Sorry haven't made myself clear.

When the install had completed there was the invite to go to the front office and I got the 503 so read the source and deleted files as first mentioned.

So I wasn't sure of what the hang up was but clearly it wasn't 'hung' in the normal process.