I used to run a rail station (not for Arriva). If a train is scheduled to depart at 2233, the rule is that the wheels should actually be moving at 22:33:00. That means that the doors should be closed shortly before that. Different operators have different rules. (Even a single operator might operate slightly different policies at different stations, because of varying passenger volumes). At the station I ran, the doors could have been closed at 22:32:30 but must have been closed by 22:32:40. At other stations (and with other operators), doors can be closed up to 60 seconds prior to departure.
Once the doors are closed, train crew are always instructed that they must not be opened again, prior to the train's departure, except in an emergency. I've known train crew to open the doors for a late passenger and, as station supervisor, I've occasionally given the signal for this to happen myself but rail staff who open the doors, after they've been closed for departure, face the risk of disciplinary action. (A colleague of mine once held a train for 2 minutes to assist connecting passengers. The train missed its 'slot' in the rail system and arrived quite late into its destination. Because it was running 'off schedule' it delayed other trains which, in turn, caused further delays. Our train then left late on its next journey, with further 'knock on' problems. Our company had to pay for all of the 'delay charges', resulting in a �5000 bill because of an initial 2 minute delay).
If you complain to Arriva, they'll consult the Network Rail computerised record system to see if the train left early. (There are actually two independent systems and they'll check the times on both). If it did (even by a minute), you'll get a refund and (hopefully) compensation for your inconvenience. If not, you're probably not entitled to anything but Arriva might make an 'ex gratia' payment anyway. So it's worth a try.
<