Here’s one for you lot. 
My car made a very strange noise while at work. 
The best way to describe it it sounds like a metal scrapeing against plastic. 
Drive down the road and it cleared it self. The engine now sounds normal again. 
It’s the 2 litre diesel and a 19 plate. 

Any one got any ideas at all ?

Something stuck between a brake disc and the shield which has now been dislodged?

Not sure. The car was standing at the time with the engine running. One of the lads I’m works with heard it as well from his car and he had the windows up at the time. 
The noise went in time with the engine. 
Ie I reved the engine and the strange noise went with it !