Neil,
It is exactly as Plamen72 is portraying it. If you try to resize, Pin, or unpin tiles in Metro the new context menu does not appear. I wouldn't have noticed but I had to stop using start8 after the last update because my taskbar kept corrupting to the point that I constantly needed to kill explorer to get any work done.
Warmest Regards
I am rather more concerned with your issue with Start8. If you are having an issue with that please report it to support so we can investigate it. Do you mean the 1.4 update to Start8?
Regarding the right click menus in the Win8 start menu, we have fixed this internally and when the update has passed QA we will be releasing it.