Brake pedal clunk

[Skull]

Hi, my first berlingo after changing my dead car.  I’ve a 2015 1.9Hdi 75 and the brake pedal gives a metallic clunk when released. I’ve tried to search the forum for previous posts but couldn’t see any although I have no doubt there are lots.  Is it a pedal spring, missing rubber bumper issue or something different? If anyone has had this then what’s the fix?  Thanks All