I was really disappointed when this wasn't included in EMI's CD rerelease program of Hawkwind's UA LP's. This cut 'n paste from Wikipedia may explain why ( could be bollocks, mind )....
The original UK master tape for the album was apparently lost or destroyed some time after the original release. The album was eventually released on CD in Britain on the Dojo label apparently as a vinyl dub. A second version was later released on the Canadian label Griffin Music, apparently taken from a first-generation copy of the original master.