Thanks for your comments dollarman and crashy.  I've spent the morning speaking with the council building services dept and many building surveyors.  Both are permitted by law to issue building permits.   The council was very down-the-line and said "As soon as you pickup a hammer or glue something a permit is required".  The building surveyors were more practical and said you only need a building permit if altering the structure.  I think the answer is to minimise structural reno work, and if needed, keep it less than $12,000 (in Vic).  If the value exceeds $12k, find a friendly builder as dollarman alludes to.