This paper is based on findings of a Welsh Assembly Government funded review of children's independent advocacy services in Wales with reference to their involvement in complaints made by children, or by their parents or carers on their behalf, about local authority social services. It draws, primarily, upon qualitative interviews with local authority children's complaints officers, whose task is to receive complaints or concerns, field these to appropriate social services staff, maintain oversight of their progression and keep complainants informed of developments. The paper describes the challenges that complaints officers perceive children encounter in moving complaints forward, especially in a context where independent advocacy services are involved and where these services are viewed with some suspicion by social services staff. It suggests that complaints officers play a pivotal part in managing the sometimes contested and complex interface between service provider and child and may do so from a position of limited authority and influence. The role of complaints officers in engaging with complainants and their advocates, and with those colleagues implicated in complaints, has rarely been the topic of research. This paper provides accounts from these key staff that help illuminate the tensions and difficulties that can enter the children's complaints process.