I tried to do a video this morning but it was neither use nor ornament. I’ll try again in better light.
The rattle lasts one minute, and the whole engine seems to get smoother when it stops. However it started earlier, I stopped the engine after a couple of seconds and restarted and the noise was not there.
It’s difficult to diagnose as the noise doesn’t last long, and then you have to leave the car around 8 hours before it does it again. I’ll aim to get a video soon and post the link up.