Since my car last went into my local OPC I've heard a faint whistling sound coming from somewhere near the rear passenger side wheel. Yesterday I went to have a look expecting to find a leaf in the vent or something on my tyre but I've just noticed that behind the vent there is a slab of plastic;

The only side has a hole with what looks like an intake fan;

I'm not on the best of terms with my local OPC at the moment so before I go in and accuse them of not putting the car back together properly I thought I'd try and check to see if this is how the car should be or not?
I can't seem to find any pictures or mention on the internet with my shoddy Goggle skills.
Any ideas?

The only side has a hole with what looks like an intake fan;

I'm not on the best of terms with my local OPC at the moment so before I go in and accuse them of not putting the car back together properly I thought I'd try and check to see if this is how the car should be or not?
I can't seem to find any pictures or mention on the internet with my shoddy Goggle skills.
Any ideas?
