In this doctoral research, two EFL teachers explored their beliefs about coursebooks and their actual coursebook use in class through data-led, collaborative practice. The presentation informs about how the research topic evolved and led into the selection of formative intervention research methodology and data collection tools and procedures encompassing semi-structured interviews, metaphor elicitation, stimulated recall, reflective conversations and journal writing. Another focus is on the analysis of the observed, spoken and written data. The observed data was analysed deductively benefitting from pre-established codes. For this reason, a research informed framework to identify adaptations was developed. Spoken and written data were analysed using first cycle and second cycle coding methods; the emerging coding categories were finally allocated to themes. Additional steps to strengthen the trustworthiness of the study are reported.