Whose responsibility is it to provide and pay for Personal Protective Equipment (PPE) ?

It is the student/guardian's responsibility to buy PPE.

Agency workers will only be responsible for providing their own personal protective equipment if they are genuinely self-employed. (People who are self-employed for tax reasons, but who otherwise work in an employee-employer relationship will be regarded as employees for these purposes). In all other circumstances, the law provides that employers must ensure suitable PPE is provided to all employees if they could be exposed to health or safety risks while at work, except where, and to the extent that, such risks have been adequately controlled by other means that are equally or more effective.