Rights to all versions of 1984 (including the BBC version, and this one, the 1956 film) are apparently under control of the Orwell estate.
They apparently loathe the 1956 version, and it's unlikely to ever receive a legitimate release. (I'm reasonably certain that it's not been seen on British television in the last twenty years, whereas the BBC version has aired a few times since it was originally transmitted).
They've refused permission to allow the release of the BBC version on DVD, apparently because they didn't want to cannibalise sales of Michael Radford's film version.
Orbit are a bottom-feeding outfit which releases a lot of material that they would claim is in the public domain (the Rathbone Holmes films, AFRICA SCREAMS, etc, for example). The reality is that it often isn't, but there isn't anyone around with the willpower or legal clout to challenge them.
A list of their shameful tat can be found here:
Sendit.comThey're usually none-too fussy about their source material, and sometimes watermark their presentations, to further add insult to injury (which is, as another reviewer most eloquently put it, "like a spaniel piddling up a tree to stake a claim on it").
The BBC version was due to be released by DD Home Entertainment, and at least some of the restoration work had been carried out (the original film inserts - which, miraculously, still exist - had been inserted into the telerecording, and the video sequences had been processed with VidFire, to restore the original video look of the play).
Since then DDHE has had financial problems, and is now under new ownership. I'm sure they would still like to release (the BBC 1954) NINETEEN EIGHTY-FOUR, if they were allowed to. It may require re-negotiating with the BBC, and it's possible that the BBC wouldn't now license it to them, anyway.
Since the Orwell estate don't apparently have any fundamental objection to the release of the BBC adaptation, I wouldn't completely rule out its release at some point.
The BBC's 1965 adaptation of 1984 (starring David Buck as Winston Smith) apparently no longer exists.