Just some feedback other folk in Perth in need of speaker repairs might find useful:
I acted on Peter_F's recommendation and took my ProAcs to the Speaker Doctor, Jason, in Osborne Park. I'm delighted to report Jason did a fantastic job replacing the bass surrounds, and his pricing was way less than I had anticipated. Further, he responded to emails promptly and had the job finished in accordance with his stated lead-in period of 3 days. I would not hesitate to return to him if ever I need more speaker repairs, and I join Peter_F in highly recommending him.
Thanks again to Peter_F for pointing me in the right direction.
PS: If anyone could advise me on whether there is a section in StereoNet for recommending repairers, would be appreciated. Excellent well-priced service is not easy to come across, and I would like to add the Speaker Doctor to any list of publicly recommended repairers for his benefit and that of other Perth-based audio freaks.