Books in First Flight Level 4 series

A silly sequel to The Sled, The Blue Door follows the further adventures of Fox and the Rabbit as they travel to the city to visit Fox's uncle. Fox hasn't seen his uncle since he was a pup, but he can recall the wonderful stories his uncle used to tell. And he knows that Uncle lives in a house with a blue door, so he should be easy to find. And sure enough, when the two come to the city, they find a house with a blue door. And inside lives an old gentleman badger who seems surprised but very pleased to entertain a long-lost nephew and his friend. But when they sit down for tea, Fox eagerly recalls his favourite stories. Uncle begins to look confused; he doesn't remember any of those things happening to him. And...come to think of it, Uncle actually doesn't remember having any nephew, let alone one of the long-lost variety.