IMHO, racv + nrma sucks. Best to get call a mechanic that you know that is reputable and organise an inspection and get the seller to take the car there, or ask a fellow mechanically minded Ozhonder'er to help you out for some beers or $$.

Then fly over, on the premis that if you like it you will take it there and then. Have a cheque written out for 80% of the agreed value that you would pay for the car after all negotiations + ~20% of the final value in cash.

If you don't like the car, dont buy it. If you do, then buy it on the spot and take it home, if you don't like it but still want to buy it, try and renegotiate with the seller using the 20% cash you have.