Re: The nth time the unfinished Shada has been completed
The first reconstruction was available on VHS in 1992. It added narration by Tom Baker. Details are provided at Wikipedia:
"...Some years later, Nathan-Turner eventually set out to complete the story in a fashion, by commissioning new effects shots and a score, and having Tom Baker record linking material to cover the missing scenes. The resulting shortened episodes (of between 14 and 22 minutes each) received a 111-minute VHS release in 1992. In its UK edition, the VHS also was accompanied by a facsimile of a version of Douglas Adams's script. The release was discontinued in the UK in 1996."
https://en.wikipedia.org/wiki/Shada_(Doctor_Who)