This paper introduces a heuristic case study, reflecting on the use of the Interpersonal Process Recall (IPR) method as part of An Internet of Soft Things, a multidisciplinary design research project working with the UK mental health charity, Mind. The three authors represent three different disciplines within the projectPsychotherapy, e-Textiles, and Human-Computer Interaction -and naturally bring their own experiences and expectations to the multidisciplinary team process. The aim of the project is to develop, through practice, a methodology for a Person-Centred Approach to design, informed by the theories and practice of Carl Rogers, and thereby to address the increasing need for researcher reflection in Participatory Design. The paper outlines the project and describes our experiences of IPR within it; it discusses how we are taking this work forward and closes with some guidelines based on our personal observations in working with this method.