Here is a picture of a wall in the office. These are the episodes in various stages of production for Driver Dan's Story Train.
First is the episode production letters, then the script number, episode title, story title then the writers initials.
The lines indicate delivery (to the BBC) blocks. For example AW, AX, AY and BA were all delivered together. (AN, AO, AP had been delivered at the time the photo was taken).
This was before some of it was rewritten by Mr John with his incredible neat hand writing. If you look closely you can see an early version of Driver Dan.