OK, so one sensible suggestion would be to enforce the standard By-Law that applies to all (NSW) Strata Plans depending upon their date of Registration, where the one for Plans Registered in 1996 states:
Garbage disposal
An owner or occupier of a lot:
(a) must maintain within the lot, or on such part of the common property as may be authorised by the owners corporation, in clean and dry condition and adequately covered a receptacle for garbage, and
(b) must ensure that before refuse is placed in the receptacle it is securely wrapped or, in the case of tins or other containers, completely drained, and
(c) for the purpose of having the garbage collected, must place the receptacle within an area designated for that purpose by the owners corporation and at a time not more than 12 hours before the time at which garbage is normally collected, and
(d) when the garbage has been collected, must promptly return the receptacle to the lot or other area referred to in paragraph (a),
(e) must not place any thing in the receptacle of the owner or occupier of any other lot except with the permission of that owner or occupier, and
(f) must promptly remove any thing which the owner, occupier or garbage collector may have spilled from the receptacle and must take such action as may be necessary to clean the area within which that thing was spilled.
This By-Law requires residents to each “work” for their own benefit, and if they don’t comply, then the Executive Committee (E/C) could meet and determine to issue offenders with Notice to Comply with a By-Law, and whilst that could lead to Mediation that might just result in the polite and sensible solutions that you seek.
You could additionally talk to your Council’s Health Department about your issues, including about one bin/lot as the By-Law implies, and they could lean on the E/C, but be careful with this as the By-Law also places some obligations on the Owners Corporation and it would need to ensure that those were in place and fully compliant.