I didn't even know this company existed until my rottie tried going out the car flap on Christmas eve! Even better, I didn't know you could just buy the flap, I thought I'd have to get a whole new unit. Even though my car flap is about ten years old they still had replacement doors. I thought it might be tricky to fit, but I read other reviews that said it was easy, and although it feels like it won't go in it did actually only take me a few minutes to fit it. Ordered it 7pm on 24th Dec (thur), arrived 2nd Jan, which is very good when you consider all the non-working days. All in all very pleased.