Hi. This is my first question to this forum.
My house was built in the 60s and has 2 plaster ceiling vents - one in the bathroom and the other in the kitchen. The bathroom vent in particular let's in the horrible paper mulched insulation dust as well as spiders. I'm looking for ways to cover them up without them looking super ugly. The ceiling spaces are difficult to get into to cover them from within the roof cavity, so I don't want to do that. I've thought of a painted board, plasterboard, plastic type board, but don't know what would be best. I'll attach a photo of the kitchen vent, but they're both the same.

Thanks