Timmy and his magic leg

Four friends all aged 7; Timmy, Maisie, Nelson and Kirsty share lots in common. They all live on the same street, go to the same school and are in the same class. They all love playing and having fun together and they all have a disability or life-altering condition. Timmy wears a prosthetic leg, Maisie uses a wheelchair, Nelson is a type 1 diabetic and Kirsty wears glasses to correct her extremely poor vision and had an anxious persona. They are the best of friends and don't let their disabilities define them. They are inseparable from each other both in and out of school. One Saturday morning they discover that the disabilities they have can and will be used to help them conquer magical quests and rescue the doctor who made Timmy's prosthetic, and his assistant who have been captured by a wizard. That morning the friends want to build a castle made of boxes in Timmy's garage and discover that one box has Timmy's first prosthetic leg in it. In the box they also find a magic spell written on a note. The children do what the note says, repeat the spell and out of nowhere comes a big, talking spider who has come from the magical lands to tell them about their mission. The spider tells the friends how 'Timmy's first special leg' [prosthetic leg] they have found is magical, after having a magic potion spilt on it by the doctor who made it. That doctor and his assistant are now being held captive by an all-powerful wizard who took a grievance against the doctor after the wizard caught him using his potions to travel to lands to obtain magical ingredients without his permission. Unknown by the doctor but these lands belong to the wizard, as do all the ingredients he took without asking. The wizard now wants a list of objects gathering before he will release the doctor and his assistant, but each object is guarded by monsters and beasts. The four friends who are joined by Maisie's talking guinea pig will use the magic leg to travel to each land and retrieve each item on the list