Noticed that Michael De Looper's catalogue of Australian album releases under the EMI / Harvest label, give a release date for this album of February, 1979. The Wikipedia entry for this album gives the date as January, 1979.
That's right ppint but they also defied the laws of physics because when they hit Mach II they actually slowed down and turned into a balladeering pop band. Look out for my new book "Quantum Physics and Pop Music" where I explain how the expanding universe and stretching of time turns once frenetic high energy artists into crooners of the Perry Como(tose) mold.