What an idiot I am.... sorry they are 285 not 185. From the audi app, spec for wheels on car from factory were 285.45.20.
Doesn't make much sense as even that wouldn't seem to be a match with the spare. Suppose either way whether it was OK with original wheels its not right with having 21s fitted now....
Either run flats when the tyres are due a change or some cans or foam....