It is certainly rare - though I have no idea on the value, sorry mate.
Is this the tape you have: http://www.starwarshomevideo.com/2018/11/star-wars-uk-video-2000-v2000-1983.html ?
This may contain some useful info to you: https://www.youtube.com/watch?v=UUo3_sDX-rU (Nathan Butler youtube channel)
The starwarsforum.co.uk - a UK Vintage Star Wars Collecting Forum may be able to give you some clue on the value etc.
There is also the https://forum.rebelscum.com - US-based; yet larger Star Wars collecting forum.
(or hopefully there may be someone on here able to chip in with some info…)