Both pipes are blowing well thanks, Gav. And I can't see any damage to the exhaust system, but I'm no expert so I'll visit the dealership I think. Many thanks.
At low speeds a horrible stink comes into the cabin (2008 X5 65k miles 3.0d). I'm guessing a need to get the exhaust system looked at, but does anyone have other thoughts before I phone the dealership? It's really nasty, as if something has died in the ventilation intake. Would be most grateful for any ideas.