I've acted as chairperson on an Owner's (Body) Corporate. Webb Plumbers are specialists in apartment buildings and in this field. They understand the Owner's Corporation rules and realise how to direct onus to the source as to "Common Property" and or "Private Responsibility." They also are roof and gutter specialists, hence no requirement to have a roof inspection unless you are looking for a 2nd opinion. One word to describe them: "Professional". They also guarantee their work. Quality comes at a price. Knowledge and professionalism is complimentary.
Cheers
Tony