Title: The Crooked Sixpence
Series: The Uncommoners #1
Author: Jennifer Bell
Publisher: Corgi Childrens
Publication Date: June 2016/Jan 2017
Synopsis from Goodreads
When Ivy Sparrow’s grandmother Sylvie is rushed to hospital, Ivy and her annoying big brother Seb cannot imagine what lies in store for them. Returning to Sylvie’s house, they find it has been ransacked by unknown intruders – then a mysterious feather scratches an ominous message onto the kitchen wall, and a very strange policeman is determined to apprehend them . . . with a toilet brush. Ivy and Seb make their escape – only to find themselves in a completely uncommon world.
The forces of evil are closing in fast, and if Ivy and Seb are ever to see their parents again, they must get to the bottom of a family secret as shameful as it is incredible . . . before it’s too late.