@richpriest yeah. Turns out it was the Trend Micro protection stuff on the Deco that was blocking it (no idea why they'd be blocking Activision or EA). Turned them off and it worked straight away....

Anyone know how to stop the M9 Plus blocking access to PS4 online games? Can access PSN, PS Store, download things etc but can't access any online feature of any game. If I tether to my mobile, works...