More noises.
A fairly loud continuous knock that gets louder/faster the faster you go- slows right down when moving slowly. It pretty much disappears under heavy braking and accelerating, and is loudest when you lift your fit off the accelerator.
I should add that the car is booked in next week, so I'm not after an Internet diagnose as I appreciate it could be anything. Knowing nothing about mechanical bits, I'm just curious as to what it may be.