Always ask all persons working on the Common Property for the details of their Legal Liability Insurance (Insurer, Policy No., Expiry Date) and where appropriate for details of the Trades Licenses held by themselves and by any employees or sub-contractors who will be on-site during the works.
If they can’t or won’t supply those details, don’t use them!
Because if they’re uninsured and/or unlicensed and suffer an injury during the works, they may well decide to sue the Owners Corporation (O/C) or the Executive Committee (E/C) [or both] perhaps on the basis that it didn’t provide a safe workplace. That could cost the O/C and the E/C Members a fortune if the O/C’s Insurers decline the Claim, and cost those Insurers a fortune if they accept the Claim whereupon they’d likely increase premiums or worse still refuse the Policy come time for renewal.
The fact that Strata Managers do ensure that all Contractors working on a Plan’s Common Property are properly insured and licensed, and often charges them a percentage of the job cost to be one of its “preferred contractors” (that of course flows-on to the O/C), all leads to the higher charges that you’re experiencing.
As for the Contractors you might select to work on your own townhouse, the consequences of using uninsured and/or unlicensed people could be precisely the same (as above) if something goes pear-shaped, but the consequences are upon you as opposed to upon all four (4) of the Proprietors in your Plan, as the Owners Corporation, in the former example. That’s why your O/C and its Strata Manager need to be so extremely thorough.