These were the bushes I fitted. Obviously specific to the diameter of the fitted ARB.
https://rover.ebay.com/rover/0/0/0?m...2F402110953874
I removed all the remnants of the bonded bush from the ARB before fitting.
I’ve read of this lasting for a good long while, but if it doesn’t I’ll buy the OEM bonded ARB from Audi.
Update 2 on the noise levels re: undertray, I’ve noticed a slight increase/change of noise in heavy traffic. Nothing major.