G-Sync/Freesync Issue (PC)

So i've figured it out and will leave this for users having the same issue.

I scrubbed the system driver using DDU .. please see https://www.guru3d.com/files-details/display-driver-uninstaller-download.html

...prior to reinstalling the graphics card driver I used CCLeaner to scrub the registry.  https://www.ccleaner.com/ccleaner/download?source=cpc&gclid=Cj0KCQiAkKnyBRDwARIsALtxe7jfrQ1vUmdG00ZLccPMQlWIOLqx1k6jAhcFiJpgcQ1A8SmxHRNDYWUaAifLEALw_wcB

Make sure you use the registry cleaner on the left hand menu

I reinstalled the display driver directly from nvidia https://www.nvidia.co.uk/Download/index.aspx?lang=en-uk

Now from there prior to restarting the game I restarted (may or may not be a primary factor there)

Worked.  Back to normal.  ffs ... a full scrub and reinstall sorted it... hope this helps some else as it was doing my noggin in