Yep bulkhead around the vents below front windscreen, chassis particularly at the rear - take a big screwdriver or hammer with you when you view to give it a good bash, make sure it's solid and not being held together with underseal.
Other than that just normal stuff you would look for on a car - gearbox (whines crunches etc) check engine for excessive smoke - all Tdi smoke black on start up but should clear straight away, make sure it pulls well and doesn't show any signs of hesitancy or limiting.
good tip cheers. ye need to get in afew to see how it pulls to see what they are spose to pull like