This research developed from a co-produced project called Moving Social Work. The purpose of this ongoing project is to train social workers in how to promote physical activity for and to disabled people. The first stage of the project consisted of building evidence to design a training programme prototype. As part of this stage, a Delphi study was conducted to ask leading experts about what should be included in the prototype. Questionnaires were sent to participants until consensus was reached. In reflecting on the results, people involved in the study commented that there was more about the experts’ opinions than percentages of agreement. Our co-production partners resolved that the Delphi was insufficient and called for detailed conversations with the experts. In response to this call, follow-up interviews with 10 experts who participated in the final questionnaire round of the Delphi were carried out. The interviews were co-produced, dyadic and data prompted. Dialogical inquiry was used to frame and co-analyse data. The results illuminate the capacity of qualitative research to justify, rectify, complicate, clarify, concretize, expand and question consensus-based evidence. The implications of the results for Moving Social Work are discussed. Beyond the empirical border of the project, wider contributions to literature are presented. As part of these, two key statements are highlighted and warranted: dialogical inquiry supports the practice of co-produced research, and Delphi studies should be followed by a Big Q qualitative study.