2003 Renault Megane A noise

I keep on hearing a noise coming from the glovebox and it keeps on making a knocking sound I have took it to
One of my friends who works at Mercedes and said it's something stuck in the fan sister but it's like metal on plastic but I'm wording because my mot is due how would the cost be to get it done and what advise would I suggest to do it's been doing this for over 3 months and I think it's gone on
Long enough