Have uninstalled, reinstalled, left the beta and turned off and on notifications in settings. Any suggestions?
Maybe give this a try?
Aha! And I did change some battery optimisation settings the other day so that will be why. Thanks @16bitkieran! 
I seem to have the inital notifications but they disappear after a short time. I have tried the above fix and see if this helps at all. Done the uninstall reinstall etc