The concept of 'professional boundaries' -- widely used in sectors where professional relationships between adults are regulated -- has not commonly been drawn on in higher education (HE) to understand and denote appropriate relationships between faculty or staff and students. Nevertheless, in recent years the question of how to regulate sexual and romantic relationships between faculty/staff and students has been a developing policy concern within HE institutions internationally. In order to contribute to empirically-informed policy development in this area, this article explores students' levels of comfort with different sexualised and non-sexualised behaviours from staff/faculty, drawing on data from 1492 students from a national survey carried out in the United Kingdom, initially published in the National Union of Students' report "Power in the Academy" (2018). New analysis on this data is introduced, outlining scales of 'personal' and 'sexualised' interactions, which reveal the patterns of comfort and discomfort across different demographic groups of students, most notably women, LGBTQ+ students, and Black and Asian students. The analysis identifies areas of interaction with staff/faculty that are of concern to different groups of students, calling into question existing policy frameworks such as conflict of interest policies and varying levels of regulation for undergraduate and postgraduate students. In the light of these findings, the article makes two recommendations: first, that training on professional boundaries should be included in higher education teaching qualifications, and second, for the development of shared norms around professional boundaries within academic departments and professional societies.