I have had three separate concreters do work at my house , carport slabs , pathways , driveways all ranging in price , i went cheap on my first concrete pour and it cracked in 3 directions , the contractor was out of the messenger and the concrete was Maltina quarries Lesson learnt
My last concreter was a great find , really reliable concreter Andrew 0400066651 ( Adelaide Concrete Specialists ) who did my driveway in plain concrete and also boral pebble finish concrete around our pool about 10k worth , sounds expensive but quality was outstanding and good mid range price can highly recommend them http://www.concretedrivewaysadelaide.com.au or http://www.adelaideconcretespecialists.com.au .
They also do site prep all that biso .....
My only advice is what Andrew mentioned - make sure you get heavy duty mesh - 76 , 100 thick slab with 32 MPa Concrete *ONLY BORAL OR HANSON* - anything less and the slab will be compromised and you pay for what you get .........Oh BTW I'm a sparky not a concreter
Hope this helps a bit .....