Soldato
Thanks mate! I'll give it a try...I used this app to find sneaky notifications: https://play.google.com/store/apps/details?id=com.coconuts.pastnotifications&hl=en_GB
I noticed I kept having a notification which popped up for a split second and disappear before I can even check every couple of hoirs or so, even after rebooting the phone. This app showed me it was Google Play Music messing up. Cleared the data on the app and solved it.