According to the list of characters in the front, it was the Fourth Doctor and not the Third that had this adventure.
For those Brits who have never seen the Pinnacle version, I reproduce some of the priceless back cover and character descriptions beneath .
From the back covers, for us clueless Americans:
Doctor Who is a mysterious, zany and very mature Time Lord (750 years mature to be exact) who hurtles through space in a stolen Time Machine. Since there's a problem with the steering, he never lands exactly when or where he plans to. This, along with his desperate desire to bring law and order to the galaxies, and his insatiable curiosity, consistently places him in weird and often wild circumstances.
Regarding the characters:
The Fourth Doctor Who
This episode features the fourth Doctor Who, who has survived three reincarnations. The long, trailing scarf, the floppy wide-brimmed hat, the mop of curly long hair and the wide-eyed stare--all these are the obvious trademarks of the fourth Doctor Who. Along with a delightful mix of personality traits--genius and clown, hero and buffoon--the fourth Doctor Who combines the best of all who preceded him.
Sarah Jane Smith
Sarah is an independant freelance journalist. She has a mind of her own and once, while in search of a story, stowed away on Doctor Who's TARDIS--and ended up in the medieval past. Forever swearing she will never again set foot in the TARDIS, Sarah cannot resist the Doctor's plea that she accompany him one more time. While Sarah appears quite invulnerable, she really does need a bit of protection now and then.
Brigadier Alastiar Lethbridge-Stewart is the Commanding Officer of the British branch of UNIT. UNIT, by the way, is the United Nations Intelligence Taskforce, created to protect the planet Earth from extraterrestrial invasion. The Brigadier is everyone's idea of a the typical British Officer--his voice is clipped, his manner is abrupt, and his mustache is very neat. But he is hardly robot-like. He's really very fond of the eccentric Doctor but sometimes he finds him very difficult to work with.
There's also an introduction to the character written by Harlan Ellison.
I think Pinnacle only released a dozen or so of these...they were quickly replaced by Target imports. But they were easily findable in the bookstores I frequented in high school and at one point I had a complete mixed set of Pinnacles and Targets. I regret getting rid of them now. :(
Crossposted to sarahjane_fic.