As engineering educators pivot towards implementing evidence-based pedagogical strategies, group work - or collaborative work - is being increasingly used in undergraduate classrooms. In mathematics, collaboration is a crucial disciplinary practice. Participation in collaborative learning not only correlates with better academic performance and deeper conceptual knowledge but also leads students to adopt better learning strategies. Moreover, working in groups can improve students' intrinsic motivation and self-efficacy and lower mathematics anxiety. Despite the evidence, the implementation of group work in higher education mathematics courses has been slow, in part due to students' reluctance to engage in group work. This study describes the implementation of group work in a second-year university mathematics course taught in a flipped format, at an engineering university. We use quantitative and qualitative survey data from a student survey (N = 33) to analyse their perceptions of group work. We find that students are perceptive of the benefits of group work and especially value its affordances for access to feedback. Despite their positive experiences, we also find that students remain reluctant to group work being used more generally in other mathematics courses. We propose that even when students successfully participate in group work, they may not perceive the transferability of the skills they develop in the process. We suggest that teaching practices supporting those competencies and making them explicit may be necessary to improve student perceptions of group work beyond the classroom.