This is unfortunate as it's one of Barnet's commuter zones and the bay is restricted only from 11am to noon.
What were you getting as loading is an exemption.
Otherwise you'll probably have to grovel saying you are a resident and just parked briefly to get something.
Yes, council guidance usually says a vehicle should be observed for up to 5 mins in some situations to see if there is exempt activity but if there was no exempt activity... you can get away with it by encountering the CEO but they may have started to prepare a PCN you'll get by post if you drive away.