This article describes research instruments that facilitate the description of teachers' beliefs and practices and their use with further education (FE) mathematics teachers. They consist of linked questionnaires aimed at both teachers and students, validated by cross-referencing with more open questionnaires and with classroom observation. They aim to provide cost-effective, systematic approaches for analysing beliefs and behaviours and offer means by which representative teachers may be selected for observation or interview when evaluating novel educational designs. They also provide scales that may be used to measure changes in teachers' practices over time. In the study of FE teachers they present a varied portrait of beliefs but a consistent, teacher-centred picture of practices. Most teachers stated that they felt unable to teach in their preferred style, owing to a combination of perceived constraints: from the curriculum, from students and from the general FE culture. These aspects need consideration in future professional development designs.