Cheers, thanks to all who are helping on this. It gets stranger. I replugged it all in again and ran the code again (this is the demo code from the OLED site) and it started to run the demo. 
The only thing I can think of is the plug wasn’t seated all the way, this feels right up there with turning it “off and on again”. I will keep on with the demo code, but at the moment it seems to work. Thanks again to the clever people in the forum.
