Welcome to the forum Adam, you'll find the members on here are a friendly and helpful bunch :)
The Q7 is a lovely car and you've got a nice spec :)
Hypothetically the timing chain should never need replacing as long as the car has been serviced as per the schedule. A rough running engine can be caused by a stretched timing chain and replacing it is an expensive job.
As your Q7 has an automatic gearbox it's worth checking the gears are smooth both in manual and automation mode. On top of this it's worth checking the service history bro see when the gearbox oil was last changed.
Obviously the Q7 has Quattro and as such it's important that this works correctly as the system can be sensitive and can even be damaged by mis-matched tyres on the same axle or uneven tyre wear.
Here's a couple of YouTube videos which maybe useful:
Hope I've helped :)
Cheers
Steve