I've just gone and knocked my work parking permit out of the wee clip on driver's side of windscreen while wiping with demister cloth and can't find it now.

I saw it fly across to the passenger side where I assume it has slipped down the gap between the windscreen and the dashboard. Does anyone know if this is likely to cause any problems with fans or anything behind there as I can't see any way to easily retrieve it...

Thanks.

Think you will be safe. It will be stuck behind the black bit of your screen and the dashboard. All the fan stuff is enclosed so you have no worries about that.