OK I found the "fix"
When I went to the git webpage, I stupidly used right click, "save as". This saved the webpage and not the actual file
Having opened in notepad and compared to the original, it was obvious what the problem was. I copied and pasted the info directly into the extensions file.
Also note that you need to right click on the file > properties and click "unblock file" checkbox in windows 10 on each file.
All working now...