tdi is a very long lasting engine if its serviced regular,at that miles i might be tempted to look at crank bearings and cam belt,if it starts well it still has much life
I suppose it depends on what the seller is asking for it. As James says if it runs well it's worth a punt as you can always replace/re-build the lump at a later date if needed. You can get caught out though, when I bought a V8 RRC years ago it ran like a Swiss watch but 2 weeks later a head gasket went … luck of the draw
Got 204k on my fender, look after the fluids and service parts and don't drive like a James Blunt and you'll be fine - notten in the mechanicals that cannot be fixed just pay attention to the tin worm.