Hi guys, thanks for all the advice. In the end I got the engine replaced by a wreckers called Imlach's in Clayton. Cost was $2500 for an engine which had done 50,000km, labour was $770 and there was a few other bits and pieces for another $200 or so. Overall very happy with the job these guys did, would highly recommend them. Service and communication was outstanding and a 6 month warranty on the new engine and the work to top it off. Cheers.