Conor, Check the bushes in the Track Control Arm. I had this exact same problem, and yes it had passed an MOT about two weeks earlier and they did not spot the excessive wear in the lower balljoint that had been caused by the track control arm problem.
Do you notice the car skipping when turning full lock at low speed in either forward or reverse.
Get checked it immediately, the balljoint on mine actually parted and it was a swine to get home. Took the Green Flag people
5mins to load on the truck, and 2.5hours to get it off the truck as the wheel kept jamming in the wheel arch.Kevin B