Mystery Bird Call

Hi, These days I live the life of a 'grey nomad', travelling around Australia.  Right now I am in Fremantle, WA.  I'm always in the lookout for new species as I move about, and I have come across one that is driving me nuts.  I cannot visually describe these birds as they do not sing consistently and always seem some distance away, but they do sing day and night.  This is where it gets interesting.  The call seems to have three distinct parts, always in the same sequence.  When I first heard it, I thought it was three different birds, until I realised the exact same sequence was followed each time.

The first part actually may be two parts, starting with a repeated 'alarm' squawk dissolving into a repeated 'chureeh chureeh call - a little like a Rainbow Lorikeet.  The second call is a eeeeeeh eeeeh call, rather like a claxon, or one of those awful car alarms.  The third call is a classic Noisy Minah dawn call, but much faster.  These always follow each other in tight sequence.  Can anyone identify this bird?  Help!  John C.