Thanks Scratchy45, it makes sense now and also explains why it seemed to affect only some artists. The EG roster contained some of my favourite artists so I was aware of the switch but didn't bother about why it occurred at the time. I was just happy that the albums were still in print. Mind you Polydor in Australia did not produce the same quality of records as they did in the UK or USA the reissues here were pressed on very thin, highly flexible vinyl of medium quality. The sleeves were cut down (no gatefolds) and printed on wafer thin cardboard (for want of a better word). Here's a link to my old copy of Eno's "Taking Tiger Mountain (By Strategy)" as example of what I'm talking about in regard to covers.
@Lee Wrecker - if you don't mind me butting in I think I can answer the question. Roxy Music, Bryan Ferry, Eno and other acts were signed with EG. EG's distribution changed from Island to Polydor (which even Wikipedia gets right).
What happened in 1977 that saw a lot of Island's back catalogue - like this record - re-released on Polydor? Obviously a merger or buy out of some sort but what actually changed hands? It's really a question for you PhilMH. I'm fairly certain you'll know off the top of your head.