In post-compulsory initial teacher education (ITE) in the UK, mentors are purported to play a critical role in shaping trainee teachers' professional development through the provision of regular, constructive and purposeful feedback on their mentee's teaching practices. However, the complexity of mentoring feedback practices -- socially, spatially and temporally -- situated within programmatical and institutional architectures and in the turbulent landscape of Further Education (FE), is often underestimated. Using the theory of practice architectures, this single-site case study attempts to untangle this complexity as it explores how mentoring feedback practices were realised on one post-compulsory ITE programme, examining the processes, arrangements and artefacts which enabled and constrained their enactment. The site ontological approach also examines the dynamic unfolding of mentoring feedback practices in response to these institutional conditions in time and space, concluding that their trajectory largely depends on the 'stickiness' of their relationship and congruence with other organisational practices and concerns.