Thanks for the information, I have applied the account settings as suggested however still having a similar issue. I assume the site drops a cookie holding these preferences and as such I have cleared out by web cache and cookies but it still does not work on the latest Chrome (does not honour the request for 4k video even when it is available).

I will do some further testing on a different machine and confirm back if this is just an issue with my machine or potentially a wider problem with the site.

Thanks again.