According to British Comedy Guide, the HH Special marking 350 years since the Great Fire of London will air on Monday 5th of September at 5PM, on CBBC.
Marking 350 years since the Great Fire of London in the infamous history date 1666, Horrible Histories takes a look at the story behind it. Meet Sir Christopher Wren and King Charles II along the way, with loads more foul facts and silly sketches!
https://www.comedy.co.uk/tv/horrible_histories/episodes/2016/3/
Horrible Histories TV 