I sell some rubber treatment stuff called Zymol that is supposed to prolong
the life of rubber gaskets and seals.  It is a German made product that
"releases trapped solvents and restores the rubbers original moisture".  I
sell it for $18 US plus shipping for a 5 oz. bottle or perhaps you could
locate it locally in Australia ( I could ship some to you if you wanted
though).  Let me know if you are interested.  In your area it might be a good
way to protect your investment.
Ken Wilford
Van-Again
John 3:16