- You may be looking for the Class audio story.
An unnamed story was to have been the third of four The Sarah Jane Adventures Halloween specials proposed to be aired in 2011. However, due to the death of Elisabeth Sladen, it was never produced. These Halloween specials were intended to extend the presence of The Sarah Jane Adventures by having them air after the first half of Series 5. Because Elisabeth Sladen would be taking time off, these live Halloween specials would not include Sarah Jane and instead focus on Clyde, Rani, Sky and Luke.
It would have seen Clyde, Rani and Sky join Luke in Oxford while Sarah Jane was abroad. This would lead to them investigating a haunting alongside one of Luke's university friends, Caroline. The gang would eventually end up encountering a Gargoyle-like creature.
It would have been succeeded by the last Halloween special, Phil Ford's Night of the Spectre. (REF: DWMSE 32)