N6P keeps making notification sounds & vibrating when there isn't a notification (no text/call etc)

My 3 week old replacement/as new N6P keeps making sounds and vibrating as if there's a notification (sms/email/call etc) when there isn't

Fully backed it up, reset it and ran it with only the OEM apps on and it's still doing it :(

Just tried to speak to Google but they're having tech issues with their systems, so they'll get back to me in a few hours once their sorted

Sounds like I'll have to get another replacement :-