My other car is a MINI!!!!
s3 will be identical to yours on the sump mate.
I'd start by dropping the sump and checking the pickup, but it's entirely possible it could be the oil pump that's not pumping enough.
Hopefully just the pick up, start with that and see what happens.
how long have you driven it with the oil light on?
The AGU doesn't have an oil level low sensor, so the warning you see is definitely pressure, which is very serious. If you carried on driving for 20 mins with the low pressure light on there's every chance it could be knackered, so be prepared for the worst, but conversely, I've done the same before on a car I didn't care less about, and after an oil change it ran fine and didn't knock at all.