Hey.
So common things I'm aware of...
Door locks - all Mk5s can have issues with the doors locking/unlocking properly so check thse
Rust - Front arches ALL go, and you can get rust on the sills and rear arches too, and I believe on the boot lid so something to watch out for.
Injectors go - so make sure it's running right, no misfires etc.
Timing belt is a much more frequent interval than the book suggests, so check it's been done in the last 40k miles
There will be other things I'm not thinking of rn too I'll come back if I remember!