I just did this route last week.
- You have to get off at Darwin and then you sit in the small terminal area.
- The lounge is makeshift, but quite nice.
- No security checks or immigration. You get callled back on the plane in 45mins.
- They clean the plane and there is new cabin crew.
The video posted is very accurate. Overall a great experience and easy way to get to the UK without having to worry about other country COVID requirements.