Hello there. I have a zanussi mixed fuel cooker(ZCM5200) The problem is that the seal inside the door has snapped and I have order a seal for the oven. The problem is, I want to know how to fix the new one because the old is is tightly in place and I don't know what to do to take it out. There are screws on inside the door. I wonder do I have to unscrew them so that the old seal can come out. Can you advise me on this matter.