Board Thread:The Reference Desk/@comment-43874324-20200828130153/@comment-6032121-20200828135104

These really, really aren't the reasons. They were maybe floated around a long time ago, but per the last debates, the reasons are:
 * It's technically a charity work, and it's not clear all the monsters were licensed, even if the use of the Doctor and companions certainly was, so it arguably fails Rule 2.
 * Due to a weird legal quirk, no one actually owns the prints of Dimensions in Time: its only legal release was on that one day in 1993 on television. It is thus awkward to even add image files from the story to the site.
 * Comments from John Nathan-Turner state that he viewed it as "outside the Doctor Who canon if there is such a thing", which, even if canon and DWU are different things, kinda sounds like it fails Rule 4.