Any idea what this noise is?

[nige]

Interesting. From doing some research on other forums that seems to be a common suggestion.

Any idea how much that might cost to fix? I will seek quotes of course but it would be good to have some frame of reference.

The other thing I've noticed is that the car is making a sort of metallic raspy noise between around 800-1000rpm, e.g. when taking off or reversing at low speeds. Not sure if it's related?

You know that phrase throwing good money after bad.......how many thousands are you into your 3 series now? Would you be willing to put another €1k into it?