Default [Q] What do I need running for Google Play?

I attempted to download an application from the google play site via my PC. I had to use google because the application is not on the Amazon store but have I used google play once before and it worked OK.
Having ordered the app and got confirmation I was surprised that the download did not appear on my phone.
I tried running google play store on the phone and it gave an error message that said it cannot connect.
I stopped the play store and google play services applications, cleared the data etc and tried again, even went back to system application by clearing updates but still not working.
Now the play application just starts and immediately stops when I tap it.
I have as much as possible of the toy applications disabled because I use this phone for business and I wonder if at some time over the past weeks I have disabled an application that the google play store application needs?
Other than google play store and google play services are there any other apps that should be running?
I have google play store running 1 process and 1 service and google play services running 2 processes and 2 services.
Amazon appstore works OK

Please ignore this, turns out I had logged out of googlemail and this stops playstore.
Cannot find a way to delete this post so can only edit