Hello Ciaran,
Audi’s recommendation is correct in terms of 5 years or 140k, but the important thing is - whichever comes first.
Your car is now approaching 6 years old, so changing the Cambelt assembly is now overdue.
You can take a chance and delay it, but a chance it will be, and looking at it logically, you are going to have to pay to get it done at some point, so why not now before it goes too long out of schedule.
Kind regards,
Gareth.