I've started reading Making Legend of the Werewolf, which was an end-to-end account of the making of the film, published as an educational tool by the BFI in 1976. I thought I'd drop snippets of interest here.
The first thing to note is that the story was arrived at by combining a 1969 treatment by Kevin Francis called Plague of the Werewolves (which I've seen speculation about elsewhere that it was submitted to Hammer) with a new treatment by John (Tony Hinds) Elder called Wolf Boy, or so Kevin Francis claims at any rate. Plague... is generic stuff about a young Transylvanian Baron who becomes a werewolf. The twist is that the werewolf who bit him originally is still at large, so there are two monsters on the loose. Frankly, it seems bugger all like Legend... Wolf Boy is pretty much the plot of Legend only without any mention of the Peter Cushing character, which is the best thing in the film. The script was developed with the producer, director and art director so that Hinds knew what sets would be available to him when submitting his final draft. The script was written with Cushing in mind and sent to him a month before filming, after which he sent through his suggestions for alterations to be amalgamated into the shooting script. Freddie Francis notes that Cushing likes to change his lines as he goes along: "There was very little of the original script left by the time we's finished this one..."
One of the sets used was a standing set that had been employed in a number of previous films, including Carry on Cowboy.
The BFI created a 20-minute film documenting the editing process of the scene in which Ron Moody discovers David Rintoul the morning after a murder. Sounds like a perfect Blu Ray extra ... if we ever get a Blu Ray!
The film premiered at London's New Victoria cinema on 27 October 1975, almost exactly 11 months after the film's completion. From there, it went on to play the Astoria, then on release in North London from 30 November, then South London, "and afterwards the provinces".
Sadly, one of the wolves used on the film escaped from its cage at Pinewood and was shot dead by a police marksman to stop him running onto the M4. The story made The Sun and News at Ten. Kevin Francis blamed the actions of reporters for preventing the animal's handlers from recapturing him.
Box Office figures were kept secret but, as of February 1976, the double bill of Legend of the Werewolf/Vampire Circus (reissue) was running 16-21% ahead of average takings. Tyburn had 70% cut. The Ghoul had run 20-30% above average but had only 50% cut from the double bill take.
There had been plans to release an LP of the scores of Legend of the Werewolf and The Ghoul.
Incidentally, I've heard the escaped wolf story told in re The Beast Must Die.