Three Doctors, a one off companion, space wolves and Coal Hill School.

This is a fun read but it does rather lay on the continuity quite heavily.  The First Doctor is at Coal Hill School in 1963.  There's fog.  A policeman gets sent to check on the junkyard.  The Third Doctor and the Eleventh Doctor retell part of the story.  Sarah Jane Smith is being told the story.  There's a reference to Clyde and the Doctor's fez.  And the Doctor's signet ring.  There's even a bit about the school being rebuilt and renamed as an Academy as it is in Class!

So whilst this is an entertaining, released for free, short story, is all a bit much continuity wise.