David Walliams is a literary genius when it comes to children’s literature. I have just finished reading ‘Demon Dentist’ to my little boy Joe, so it is fitting that this is also the week that I was able to see my first Walliams adaptation on the stage. ‘Gangsta Granny’ is his most popular book, and it was brought to life in thrilling and hilarious fashion at the Wolverhampton Grand last night, proving to be a treat for both the young, and they young at heart. Ben is twelve years old. His parents are a little obsessed with ballroom dancing, which leads to Ben dreading Friday nights, when he is forced…