Response from C2C to my suggestion that they educate staff about All Line Rover validity after I was initially refused entry before 9am.
Oh dear.
'I can confirm that as per the Senior Rover terms and conditions, the ticket is valid Mondays to Fridays only, excluding bank holidays and travel time restrictions apply. The £10 rover is only valid for use after 09:30 and is not valid on any trains travelling within the London Travelcard area (Zones 1-6) between 1600-1859. The £7 rover is only valid for use after 09:30.'