The Owner or Agent of the rental apartment is required to provide the Owners Corporation of your Mum’s Plan with details of the Tenant’s Name, the Term of their Lease etc (S109 Strata Schemes Management Act 1996); the Strata Manager would have that detail and of course the Landlord’s details.
It is also a condition of the Lease that the occupants of the rental apartment comply with the Plan’s By-Laws, and the frequency / duration of the noise that your Mum’s experiencing and the underground BBQ are clearly in Breach of those By-Laws.
So after taking into consideration the fact that the Strata Manager has already written to the problem tenants with no affect, I’d recommend a two-pronged approach:
- Contact the Strata Managers (SM) and request that they initiate procedures to issue the Tenants with two (2) Notices to Comply ; one for the noise and one for the improper use of the Common Property, and with the regard to the noise, ask the SM to additionally include a letter advising those Tenants that the Owners Corporation will additionally seek Noise Abatement Orders against them in the Local Court if they don’t comply fully with the terms of that Notice.
- Ask the Strata Manager to copy the above to the Rental Agent and to the Proprietor / Landlord of the rental apartment, and again include a separate letter advising the Proprietor that he/she may be held legally liable for any continuing Breach/s of the Plan’s By-Laws by the Tenants (there is a legal precedent for this), and requesting them to have their Agent follow-up with regard to their Tenant’s non-compliance with the terms of their Lease (which requires compliance with By-Laws).
Hopefully, that two-pronged approach will work, but if it doesn’t, I’m afraid that the only remaining recourse is to seek Police involvement as a back-up to the O/C actually seeking Noise Abatement Orders OR lodging an Application for Orders with the Strata Division of the NSW Consumer, Trader, and Tenancy Tribunal (CTTT) where fines of up to $550 may be imposed against the Tenants (as residents of a Strata Plan). Regrettably, an O/C is not currently able to lodge an Application to the CTTT’s Tenancy Division where eviction orders can be made, as it sounds to me like that’s what is really required in the circumstances that you describe.