I had mine serviced at 2500km.
I supplied the Castrol R 10 w60 oil and it cost A$190 .(of the A$190 about A$140 was labour.)
Also included free of charge was the partial removal of the black rubber strip under the car by some "Testa di Catzo" (probably not spelt right but you will get the guist of it.

)
I assume that your A$320 included a charge for a car for the day?
NB. Officially the 147 is not required to be serviced until 20,000 km or 1 year