We live in the age of peak sequeldom - seemingly every movie or TV show that ever had a following is seeing some form of revival on the big or small screen. But what are the sequels that never got made but should be? Whether it’s the much-demanded District 9 follow up, a revisit of the bonkers Face/Off concept, or another dream-within-a-dream in Inception, we theorise - and frankly, fantasise - about the sequels that just have to be made, but haven’t been.