ADDITION: (November 2018) Network - Region  'B' - Blu-ray: Network presents the 1979 mini-series iteration of "Quatermass" and its condensed version "The Quatermass Conclusion" on a dual-layered and separate single-layered Blu-rays. They utilized the the original 35mm negatives. The 1.33:1 image to 1080P (although wouldn't it have been in the PAL standard as a UK Television broadcast?) is rendered with a modest bitrate. It can look a bit waxy at times but also decent and pleasing in-motion. These are the four episodes of about 55-minutes each on the first disc (described on IMDb:)

Ringstone Round S1, Episode 1
24 Oct. 1979 Ringstone Round
Professor Quatermass comes out of retirement to search for his missing granddaughter and finds a world on the verge of anarchy, and an American-Russian space station destroyed by unknown forces. He is befriended by astronomer Joe Kapp and they witness the obliteration of thousands of Planet People by a beam of light at the stone circle, Ringstone Round.

Lovely Lightning S1, Episode 2
31 Oct. 1979 Lovely Lightning
Following the devastation at Ringstone Round, Quatermass hears of similar incidents worldwide and returns to London with district commissioner Annie Morgan and a Ringstone 'survivor' Isabel. En route they become separated in a shootout between rival gangs. Meanwhile, the beam of light descends again - near Joe Kapp's home.

What Lies Beneath S1, Episode 3
7 Nov. 1979 What Lies Beneath
Quatermass is rescued by a group of elderly people living in a scrap yard. At the hospital, the doctors are shocked when Isabel levitates off her bed and explodes in a cloud of dust. Elsewhere, the devastated Kapp is left alone in the ruins of his cottage and observatory. More and more young people are joining the Planet People, including the gangs that have been terrorising the cities and the soldiers assigned to keep them away from the Megalithic sites. Contact is restored with Chuck Marshall and with the Russians in the form of Gurov. Quatermass theorises that this...

An Endangered Species S1, Episode 4
14 Nov. 1979 An Endangered Species
Quatermass emerges from the car park to find the stadium empty. So many have now been harvested that the particles of dust in the air have turned the sky green. Kapp attempts to repair his equipment in order to contact the alien presence, but the Planet People destroy his efforts. They try to persuade him to join them but he refuses, convinced now that his family are dead. Quatermass, aided by Gurov, who has travelled to London from Moscow, assembles a team of scientists to find a solution. He deliberately selects old people for the task as they are immune to the...