A general class of non-linear large-scale interconnected systems is considered, wherein each subsystem is comprised of a nominal part in a general strict-feedback-like structure and a set of appended dynamics. Parametric and functional uncertainties and time delays are allowed throughout the overall system structure including the nominal strict-feedback-like parts and appended dynamics of each subsystem as well as the non-linear subsystem interconnections. The controller design is based on the dual dynamic high-gain scaling technique and provides a robust adaptive delay-independent globally stabilising decentralised output-feedback controller. The disturbance attenuation properties of the proposed output-feedback decentralised controller to an exogenous disturbance input are also analysed and specific conditions under which properties such as Input-to-Output-practical-Stability and asymptotic stabilisation are attained are also discussed.