Small Change for Stuart

Small Change for Stuart by Lissa Evans is about a very little boy called Stuart whose parents were very tall.
His mother had a new job but it was very far so they moved to Beeton.
Then his father wanted to take a walk so he took him in an old part of the town.     
In the old part of the town there was the family business of locks that now was abandoned.
His father also showed him the house of his great uncle Tony who was a magician who disappeared
when is father was little.
The last thing that Stuart's father remembered of  uncle Tony was a tin box that he left as a Christmas gift. Now Stuart tries to discover all the magic behind the box...