This paper presents an experience report of online attendance and associated behavioural patterns during a module in the first complete semester undertaken fully online in the autumn of 2020, and the corresponding module deliveries in 2021 and 2022. The COVID-19 pandemic of 2020 resulted in a sudden move of most university teaching online, at a global and large-scale level. This, combined with the need to maintain "business as usual" resulted in new levels of student engagement data for largely unchanged pedagogical processes. Engagement data continued to be gathered throughout the subsequent, phased return to face-to-face and hybrid learning, although at a lesser level of granularity. The wealth of student engagement data gathered during this time allows quantitative insights into how student behaviour continued to adapt during and after the enforced online learning during the COVID-19 pandemic. The anonymous subjects of this case study are computing science students in their final year of undergraduate study. We examine their engagement with the virtual learning environment, including engagement with recorded lecture material, attendance in online sessions and engagement during in-person labs. We relate this to both the students' final grades and the content of the module itself. A number of conclusions are drawn based on this empirical data, relating to observations made by staff and pedagogical theory. There was a moderate, but significant, correlation between engagement in synchronous online lecture sessions and grades during thelockdown phase, but the strength of this correlation has reduced in subsequent years as normality has returned. From monitoring behaviour in online sessions down to minute-by-minute accuracy, it can also be seen that some students strategised their engagement based on sessions they perceived to be most directly contributory to their assessment, placing little value on live guest lecturer sessions. During enforced online learning, the most successful students, on average, engaged with less repeat content than less successful students, instead apparently utilising lecture recordings to "catch up" with missed live lectures.