Late reply but had a very similar thing just the other day. Had driven the car and parked up but on the return journey I had a really annoying squeak and vibration seemingly from the dash area in front of me, that wasn’t there before. After hitting and pushing the dash – as you do – it was still there. It wasn’t until the next day that I realised that I’d unclipped the sun visor to turn it to the side and on returning it I hadn’t clipped it back in It was that making all that noise, after all!
JohnD