Long story short, I ended up with P2015 error a few weeks ago and got the inlet manifold replaced (2.0 TSi, 2009, 67k), then on the drive back got a loss of power, flashing MIL and some smoke!
Panic, pull over and stop the engine straight away, get the car recovered back to garage.
Turns out P0303 error (misfire cylinder 3), after some digs garage confirms it's a dodgy injector which is stuck on open. Decided it's best to replace all four injectors just in case, also done plugs and coils just in case.
I really REALLY hope this is the last of the big bills this car throws up, it's been rather unlucky so far, and I am rather annoyed that a 5 year old car with 67k on it has had so many faulty parts!