Zafira a oil filter cap

Hi ladies and gents, help for the newbie please...

My 2004 zafira 2.2 petrol has been leaking oil and today I noticed it is coming from a crack in the plastics screw on cap the houses the oil filter.

My question is... is this part unique to this vehicle or is it a generic part that fits a number of vauxhalls. I have had little joy searching online for the part.

Thanks...