Kronos (as it is commonly known in Hammer fandom) has acquired quite the cult following over the years. I first saw it on the CBS Late Movies sometime in the mid 1970s. I think it's a pretty cool film--not entirely successful, perhaps, but much more interesting than a lot of the more polished, glossy, compact productions.
I presume this is happening because Brian Clemens died last year (I think it was last year?) and perhaps someone approached his sons for the rights to the Kronos project. It had originally been meant to be a sequel but the release and distribution of the original film was so badly botched that the movie had only a spotty and intermittent appearance in theaters--plus, of course, Hammer studios was in a state of collapse by the time the movie played here, around 1974 I think. Horst Janson, who was I think German (perhaps Austrian?) plays Kronos and does have a presence that might make you think of Michael York. The last I heard, Horst was still alive and active as an actor.
An intriguing facet of the original movie was the use of some very offbeat folklore that sets it apart from the usual Hammer vampire film. I've never known if that folklore was something Clemens invented, or found in Montague Summers.
G.