On each of the side-to-back panels there are these 2 brackets (you can see one clearly-ish, in the middle of the picture) which i can't track down on the parts diagram. I have a catflap back on my landy.
Rear End Door, Tail Gate & Fittings in Series > Series 2 > Parts > Body & Fittings > Rear End Door, Tail Gate & Fittings from John Craddock Ltd (Page 3)