i rang up last week as im in similar boat but they told me you have 4 weeks to clear it and u can only drive the car for the purpose of repairs to and from workshops or vicroads.
after that he said the rego may be suspended id say if u rang up vicroads you should be ok they are pretty helpful with this stuff particularly if u tell them u cant source parts due to time of year etc.
im not sure ringing the officer would do anything cos they dont care once they issue the defect its vicroads/your problem, i could be wrong though.