Having just mentioned the Invasion reconstructions, an excuse to show the covers and talk through this classic second doctor story in more detail...
Even though 'The Invasion' is an incomplete story, with episodes 1 and 4 missing. It is, to date, the only incomplete story to be released in audio CD, video and DVD format (I think!). The story was sold abroad, so the optimistic Who fan can hope that perhaps one day these missing episodes will be recovered from a foriegn TV station clearing out their archives... perhaps.
The Who Script project introduces this story as follows:
The Invasion was to have been a sequel to a story in the previous season, The Web of Fear, and it was also intended to feature the return of two characters from that story, Professor Travers and his daughter Anne. As these actors were unavailable this lead to the substitution of two similar characters, Professor Watkins and his niece, Isobel. Further changes resulted in replacing the Yeti used in "Web" with the Cybermen, and expanding the story to eight episodes. Invasion was the fourth occasion Patrick Troughton's Doctor encountered the Cybermen, more than any other adversary. (Get the story scripts here.)
According to the Who wiki site, the story had a working title of "Return of the Cybermen" and was originally conceived as a four part story - it got expanded to eight when the next story, "The Dreamspinner", fell through (see here).
The audio CD of the original soundtrack was released with linking narration by Frazer Hines.
The video release used linking narration by Nicholas Courtney (again text of which is available on the script project link above). Cover artwork was by Alistair Pearson.
The DVD uses animated versions of the missing episodes 1 and 4 that were made by Cosgrove Hall, which had previously made The Scream of the Shalka. It also contains the linking narration of Nicholas Courtney from the video release.
This last image has been robbed from the Invasion gallery on the Beebs classic series website, here. Strangely, the only way I could get to this page was through google, as I can't find it linked through the site menus.
The Beeb's classic series website doesn't have a 'photonovel' version of this story, which is a shame. But they do have the usual episode guide page with short video clips and the odd 'original paperwork' section which I think is the shooting script (here).
You can read about the reconstruction here.