Legal advice - Can a company fire you for not agreeing to be tested?

I work for a health care provider, supporting people with learning disabilities. I have been asked to take the PCR-test on a weekly basis, but I am refusing. They have cited my duty of care and health and safety regulation, but I am arguing that stating that I am not complying with these by not taking the test is subjective. The conversation is ongoing, but I have been threatened with 'disciplinary action' and to be 'removed off shifts' so far. I have asked for clarifications in writing, are they saying they will not pay me, are they saying this will result in dismissal... but have not received this clarification yet. Any legal advice? I would argue that the mere threat is unlawful... When it comes down to it, they will probably argue they are bound by Public Health England, and I'd probably be wasting my breath talking about science, the lack of consensus, the clear suppression of science etc., so I really just want to focus on the contractual side of things... I know legal teams have helped people win cases with their employers over masks etc., I'm just curious if anyone knows where I could turn to to start getting this kind of legal advice? Thanks!