A picture of the oven hood would help. Normally, you can buy a generic filter at Migros and cut it down (with normal scissors) to size - no need to buy a manufacturer specific filter.

Matthew,

I currently don't have a picture of it, but it's the standard type that needs to be fitted into the cabinets, no metal hood if that makes sense.

Thanks a ton for the info as it seems the filter is just the sponge material and doesn't even come in a casing. Would it be this?

https://produits.migros.ch/filtre-a-graisse-pour-hotte-daspiration

Thanks so much once more

Yep, that is what you are looking for.  Normally they are grey and have charcoal inside them to actually absorb the grease in the cooking steam but indeed any will do and you just cut it to the size of your hood.

Thanks! you just saved me a ton of money (well assumption since I contacted Bauknecht and they claim I have to order it through them). But I have friends that were charged 300 CHF by their regie for not replacing it!

With that said, you seem to be quite familiar with cook top ovens? Any advice on fixing scratched ceramic cooktops? I bought the cleaner at migros and once the solution driess the scratch (looks like grey fading/wear and tear) is visible once more. 

Think it needs to be replaced? Or can i somehow buffer it out?