So this documentary is basically about making a fan-edit of ROTJ with Prowse as the unmasked Vader?
(Has this been an issue among fans? I’ve kind of taken Sebastian Shaw for granted, and it never occured to me that Prowese had any strong feelings about it.)
They actually did it, by a professional director. He asked permision to Lucasfilm, and of course it was denied. But it was shot anyway and viewed on a private screening with a few people including Prowse. They are no images of this scene in the blu-ray, because of the legal problems they would have for showing it. But there are images of Prowse during the makeup process and also during the private screening.
The documentary also talks of the reasons why Prowse was replaced by Shaw. Apparently George Lucas was pretty upset with D. Prowse because he believed that he leaked information to the press about the death of Vader during the shoot of ROTJ. Prowse always denied it.
Prowse Makeup sequence
Private screening with Prowse