In 2019, the English government embarked upon revision to the statutory Early Years Foundation Stage (EYFS) document and to associated non-statutory guidance. At the time, concerns were raised that early childhood experts were insufficiently involved in drafting the document. Consequently, an Early Years Coalition of early childhood organisations was formed to develop a version of curriculum guidance 'for the sector, by the sector'. This paper draws on contemporaneous documents and communications from the period, coupled with the author's own experiences as a contributor to this coalition's guidance. It reflects the perceived critical agency and collective action of coalition partners. Further, deploying the notion of agonism, the author considers how the diversity of early childhood representative bodies involved was conducive to developing the conditions for policy contestation. The paper concludes with reflections on the potential for further collaborative advocacy in seeking greater autonomy and professionalism, for and with the early childhood workforce.