Trickle vent - is there something missing?

[Deleted2797112]

My late father's house has 3 upvc windows with this arrangement full width at the top of the window. I'm assuming it's some kind of trickle vent as the brown piece with the oval holes slides backwards and forwards to open/close the holes. But should it look like this, which is horrible? Is there some kind of cover missing that I can buy/install and if so where can I get them and what are they called?

TIA!

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[freddiemercurystwin]

Normally you can pull the flap up or down depending on the type of vent fitted, you sure you can't close it i some way? They can stiffen up if left open for yonks.

 

[Deleted2797112]

Thanks! I don't think there's any flap. The brown piece just slides a couple of inches from left to right to allow or stop the airflow - there's no knob or handle to do it, you just have to stick your finger in one of the holes and push/pull. It's more the aesthetic appearance I want to improve. It looks unfinished as the brown vent is set slightly back from the white face of the frame as if there should be some kind of cover. It's a real dirt-trap too.