I gave up on using all available Admob plugins and have switched to Appodeal. I saw a tutorial that was only 10 months old and has received a lot of positive feedback.
Managed to build my APK using everything written in those pages but when I installed it no ads were being displayed. I got in touch with the Appodeal team and they said the existing WORKING plugin was old and had been replaced with a new one so I downloaded the new one and....Build Failed.
Moral of the story is doesn't matter how good current methods are. For all you know the next update would be released tomorrow 1 hour from now rendering the previous plugins obsolete. I've been trying to build a decent APK for 5 days now.