I don’t know if I am being stupid and missing something, but I don’t seem to be able to turn off the auto high beam once I have turned it on without flash banging other drivers.

From what I can tell once the car is started and you turn on the auto high beam by pushing the stalk forward, there is no way to turn it off again without flashing the main beam, if you push the stalk forward it turns on the normal high beam, if you pull back on the stalk to flashes the high beam.

Am I doing something wrong?

Pull it back white its actually on high beam.

Yes, what you say, @Neily03 is the only way.

If you enter a lit area whilst on auto (so it becomes dipped all the time) there's no way to take it out of auto until you stop.

Even pulling the stalk back - giving other road users a flash in the process- doesn't reset it. It stays on auto until you switch off the engine.