yeah, can see rust on those front wings. Car seems nice, advert is suitably vague so id be on your guard. as said, front arches, sills both sides, make sur eyou run your hand up inside the inner sills too. Check the brake and fuel pipes, get a torch, and get under it-these run drivers side front to back.
Look through the rear arch, you will see the rear seat belt moutning points, make sure these arent rusting.
Check the passenger foot well for any signs/smells of damp.
if you drive it, floor it. Check the rear view for smoke. check smoke on startup, but check engine feels cold first. Check for EML, will be lit if key is in the on position (so you get all the dash lights)
ensure both front and rear washer jets work - its a pain to change if the front pump is faulty. Make sure you have plenty of power, the MAF is a common failing point, as is No1 injector and CKP sensor - watch out for random stalling (i doubt these will be an issue at that mileage)
Clutch seems to last a long time, but testing that is easy. I didnt have to change mine till 124k miles.
check the drop links, dead easy to see front and back, although these are easy and cheap to change.
well, after that its all basic stuff. These are strudy cars, but as they are TDi, you want to pay close attention to that I/C and turbo. Also, check the rear exhaust rubber mount is intact, they wear really quickly, easily seen through nearside rear wheel arch.
have fun tomorrow, id take Stinka with me for sure, because i bet he could get you some money off!! :clap
**it could just be the photo, but that bumper looks wonky, and it looks like either bad rust or a hole in the drivers front wing...not a good sign (although not a difficult fix either)