Thought that 18-CD set of everything Bob Dylan recorded in 1965 and 1966 was the last word in period-specific artist box sets? Think again. Pink Floyd have announced a new box set, The Early Years 1965-1972, which will comprise 27 discs – both CDs and DVD/Blu-ray discs. It will contain seven hours of previously unreleased live audio, and more than 15 hours of video. The Early Years 1965-1972 is released on 11 November.

It’s a bonanza for Pink Floyd fans, for the amount of unreleased material included. For the first time, the much-bootlegged Syd Barrett-era songs Vegetable Man and Scream Thy Last Scream get an official release.

Arguably more exciting for Floyd fans is the release of what has been described on messageboards as “the most obscure Pink Floyd recording of all” and “the Floyd holy grail”. The music in question is eight tracks the Barrett-era band recorded for the film-maker John Latham on 20 October 1967 in London, but which he decided not to use in his short film Speak. These tracks have, so far as can be told, never been bootlegged.

Nearly as exciting is the release of In the Beechwoods, a Barrett song recorded at the same time as Jugband Blues, from the second Floyd album A Saucerful of Secrets, which has previously surfaced in low-quality abridged form.

Pink Floyd … Think how long it will take you to work your way through that lot. Photograph: PR

The set is divided into six volumes, each of which will be released separately in 2017. Cambridge St/ation covers Barrett’s time with the band form 1965-1967, and also includes the band’s 1965 recordings. Germin/ation deals with the immediate post-Barrett period in 1968. Dramatis/ation contains music from 1969, including tracks recorded for but not used on the soundtrack to the film More. 1970 is covered by the Devi/ation set, which includes the first performance of the Atom Heart Mother album for the BBC. The 1971 Reverber/ation volume includes demos for Meddle, while the 1972 Obfusc/ation contains a remix of the Obscured by Clouds album. A bonus volume available only with the full deluxe set contains early BBC sessions, live recordings and three feature films scored by Floyd – The Committee, More and La Vallée (Obscured by Clouds).

The box also comes with the inevitable posters, pictures and replica 7in singles.

Those who feel a 27-disc set is too big for their shelves or too pricy for their bank balance can also get a 2CD highlights compilation. Needless to say, that does not feature Vegetable Man or Scream Thy Last Scream, or the John Latham session. So if you’re serious about your Syd, you’re going to have to shell out for the whole lot.