Many changes in teaching practices (such as introduction of e-assessment) are initiated by school management, or by a lead teacher, but have direct impact on the learning designs of others. However, models of teachers as innovators, conducting evidence-based inquiry into their students' learning, view the teacher as initiator of change in their own practice (normally as individual). This paper addresses the question of whether such models can also be applied to change introduced by top-down processes. In this paper, we examine teacher inquiry in such a context. We discuss a case study in which we worked with the Head of Science (HoS) of a secondary school. The HoS designed a cross-curricular science, technology, engineering and mathematics (STEM) project with 57 STEM teachers and introduced Google Forms as a tool for formative assessment. We supported the HoS to design and conduct an inquiry that involved all teachers. We examine the context and process of inquiry and how it was applied. Our findings provide insight into teachers' use of tools and representations when communicating about learning design, and the implications of this for the development of learning analytics tools. They also inform the development of a method for coordinating teacher inquiry in cross-curricular projects and, more generally, in the context of top-down introduction of change.