Somthing upbeat and happy would be best. Dickon is kind of a fun, smart ace kind of guy. It might sound outlandish but when I did the show a while ago, the Guy who got Dicken sang a song from Mary Poppins. I cant remember if it was Pavement Artist or Chim Chim Cher-ee. Dicken is kind of like the way Dick van Dyke is, with the accent and odd personality. I dont know if that helps but it is an idea to go with.