Tonkin, as referenced by the URL http://www.tonkin.com.au, is a civil and structural engineering firm operating across Australia, including Adelaide, Sydney, Brisbane, and the Sunshine Coast. They provide engineering services and associated solutions. Their target audience includes construction and infrastructure development projects. The unique selling proposition (USP) of Tonkin likely lies in their comprehensive engineering expertise and localized service delivery across multiple regions in Australia, offering tailored solutions to meet specific project needs. Their LinkedIn presence suggests a focus on professional networking and showcasing their engineering capabilities.