Sounds like you're being fobbed off. Ask a friendly taxi driver to recommend a local diesel specialist to ensure the problem is sorted. Personally, I would never buy a second hand common rail diesel that's out of its guarantee with no idea how it's been driven from new. The engine sensors tend to get clogged up with carbon deposits especially when driven predominantly on stop-start trips and you can't tell if it's ever been misfuelled by previous owners!
Volkswagen has confirmed the pricing for the eight-generation Passat saloon and estate. Deliveries will begin in January 2015, with prices starting from £22,215 for the saloon and £23,745 for the estate.