Ok, under 188.8.131.52 and earlier, the sync worked fine.
The addition of the proxy changes have broken this for me, it is possibly a setting I can change, but I'll advise all the info I can to see what the story is.
I think the main point here is that my business admin uses the 'automatic configuration script' method to apply the proxy details, i.e. work proxy when I'm connected to work, no proxy when I'm at home (laptop).
So there are no actual proxy settings in the IE settings.
So when I update to 184.108.40.206 I start to get the following error:
Web request to 'https://accounts.google.com/o/oauth2/token
Obviously, I could hard code in my work proxy, but then the sync won't work when I'm at home, and vice versa.
If I revert back to 220.127.116.11 it works as expected and makes connection to Google.
I have the settings.xml and OGcalsync.log file that can be provided upon request.
Win8, Outlook 2013