How fix fast freeze door on F&P N210 freezer?

My husband just did it! He left the runner pieces still screwed into the walls of the freezer. With the transparent "door flap" in its vertical position, he prised one of the small white pieces (that has the 2 lugs that make the flap swivel) off the "door flap". Each little white piece has a hole on its outer side, and there is a corresponding bump on the flap, so the little white piece has to get itself over that bump before it will come off the flap.

Susan Favell
January 2017