Ok guys hoping you can help here, I am a bit lost now.

So problem is I am not getting notifications on my Android devices for a lot of apps, I seem to get notifications for Email and Calender and SMS but that's about it, nothing for hangouts / Facebook / Skype ect.
At first I thought it may be because I had the webpage for that app open on my PC, so shut down the pages, still no notifications?
Getting quite annoying now as its the same on my Nexus 4 and Nexus 7.

Another odd thing is when I go to the Google play web page and try to download a app neither device is listed?