Adding the UCL guidance to its staff on whether they are keyworkers which I think my place also follows:
Staff responsible for research and other activities to mitigate the effects of COVID-19 and for other essential research and supporting activity necessary to meet regulatory, legal, health and safety or other on-going requirements. This includes long-running research which cannot tolerate a break, staff looking after live animals, plants, bacterial cultures or hazardous materials; and technicians for essential maintenance of equipment and facilities.
Staff responsible for providing services for students who need to remain in student accommodation (including those who are isolating after contracting COVID-19), including catering staff, cleaners, wardens, mental health support, IT and security staff.
Staff critical to the safety and security of the university estate and business-critical operations.
It does seem illogical though to say that someone teaching a Y13 student is a key worker but a person teaching a first year undergrad is not.