[billjam]

I'm surprised that no-one has owned up to turning the engine over on the starter to pump oil out of the oil system. It will horrify some, but turning over an engine that is fully doused with oil internally isn't going to cause any damage at starter motor revs.
I have owned a lot of cars and changed a lot of oil and I ALWAYS give the engine at least ten seconds of cranking to get another litre or two out of the system, more if the oil cooler thermostat is hot and open.
On restart after adding new oil, the oil pressure rises almost instantly because the pump has fresh oil all the way up to its inlet and the engine only needs a few turns to fully charge the oil gallery again.