Well it won't be unrated because this is the UK and we don't have 'unrated' discs. From what I can tell the UK disc is the director's cut, as it contains scenes that are said only to be in that cut (such as the ambulance driver's head being smashed onto the ground three times instead of one).
Yes, the UK Blu-ray from Second Sight is the restored "unrated" cut of the film that was previously released on DVD in the USA. Among the decent set of bonus features this Blu-ray includes the same restoration featurette that was found on that DVD, showing the excellent work that was done to restore the film using recently-discovered workprint trims of the excised material - long thought lost.
It's a top-quality restoration, supervised by director Stuart Gordon, with no jarring variation in picture quality when you reach the restored sections - which is a miracle when you see the quality of the trims they had to work with, covered in damage, dirt, and grease-pen marks: all cleaned up beautifully.
The UK video (i.e. VHS) release of "From Beyond" (the last time the film saw a release in this country, IIRC) was cut by a further 10 seconds by the BBFC on top of the cuts that had already been made in America - so this uncut Blu-ray version is doubly uncut from our perspective, restoring both the BBFC and MPAA cuts.