Anyone know if co-op has been fixed or is being fixed so that not just the host gets the win on campaign races but it also goes towards all the group in co-op as at the moment its pointless playing co-op campaign. Cheers 
I play co-op quite alot with a friend of mine and as far as I know we never encountered any problems on that front. Heck, we even played events, 3-starred some PR stunts and participated in a midnight battle I had not unlocked yet. Everything was there as it should once I unlocked them and I even won the midnight battle car (which was meant to be won at the last midnight battle, I only just completed the first).
You need to have already unlocked the race in your own campaign for it to count as a win for you.
The PR stunts only work for the player who actually did it.