here's the official guidance from our intranet (slightly paraphrased to make sense):
The new return to the office criteria
Some of you may need to come into the office in order to fulfil your role, such as to attend meetings that cannot be conducted successfully online via Teams or to discuss specific projects. Others may also wish to come into the office for personal reasons, such as feeling isolated or simply because there is a lack of space at home.
There are three key criteria that can now be used in all discussions between managers and members of staff about a safe return to an office working environment:
(a) whether there is a requirement for work to occur in the office
(b) whether it is sufficiently safe for an individual to do so
(c) whether any arrangement is mutually agreeable between manager and staff member
Detailed guidance has been through formal consultation with the representative bodies that outlines the considerations to apply when discussing the need to continue to work from home or in the office.
The full guidance is available on the Coronavirus pages of the intranet, in the manager's section and can also be read here. Note, the grievance procedure is available if managers and members of staff are unable to reach mutual agreement.
Line managers should already have conducted a Covid-19 risk assessment for every member of staff that sets out whether an individual's risk is low, moderate, high or very high.
so yeah... "mutually agreeable"