Help Please!!! - Glow Plugs / EGR Valve

[HamSoup]

I've got an Audi A6 (2.0L TDI / 07 Plate) - I've had the EGR valve replaced by a local garage, then around 2 weeks later (less than 400 miles), the glow plug light appears and the DFP light came on (couldn't go past 40, high revs no acceleration). I took it back to the garage and they have diagnosed a blown glow plug, a blown DFP sensor and a clogged DFP. They are saying that the EGR repair and these new problems can't be related and it was just an unfortunate bad run. Is this a fair statement? I just want to make sure that i'm not being shafted.

Any mechanical Audi help would be most appreciated...

Cheers.