The accessibility of interactive computer-based products and services has long been an issue of concern to the Assistive Technology (AT) and Human-Computer Interaction (HCI) communities. In recent years, there have been several efforts aiming to document the consolidated wisdom in the form of general guidelines and examples of best practice. Despite their sound human factors content, these guidelines require substantial interpretation by designers, before they can generate practically useful and context-specific recommendations. In this paper, we examine how this task can be aided by blending scenarios of use and informal argumentation in the context of a structured technique referred to as Universal Access Assessment Workshop (UA2W). The paper provides a review of the technique and proposes two instruments, namely scenario screening and growth scenarios, which can be used to structure the conduct of UA2Ws. Finally, the paper summarises recent experiences in the use of these techniques in the context of a case study, which seeks to provide universal access insight to the design of a ward-based service to patient medical data.