BTW, here's an article that explains the "new" effects and includes some screen grab comparisons between the old dvd and new Blu-ray releases.
This is Hammer's reply to one persons' (not me) question about the re-do:
"Hammer Films - Hi Rick, in reply, it's about one film in particular, not multiple films. The reasoning behind the work is that key creatives who made the actual film were never happy with the finished result. The work we've done is about showing the film in the best possible way: fully restored and with some of the VFX shots enhanced. Nothing was re-shot and nothing was painted-out, which is why we use the word "enhanced" (not "replaced" or "re-created"). An early review compared the work with that of George Lucas on Star Wars and that comparison appears to have prompted very strong reactions from some fans. All we can do is repeat what we've always said: please watch the restored/enhanced version and make up your own mind. P.S. Enticing new audiences was definitely not our intent, though if the restoration brings a new audience to the film. surely that's a good thing?"