Being homeschooled need not necessarily stop you being considered eligible for widening participation. Often it’s things like home postcode, care experienced, carer, low income, first in family to uni etc not just free school meals!
My daughter did a pathology summer school at our local big teaching hospital in the summer holidays between yr 12 and 13. She got it by emailing the department asking for work experience (which they couldn’t offer) but they did offer the summer school. It was a week long; she got to see several different pathology departments, do various testing using their equipment, talk to different types of pathologists and came away with lots of information leaflets. Perhaps try emailing your local hospital, pharmacy, research centre etc asking for work experience/shadowing or summer school type programs. Be succinct, attach your CV and try many departments as it’s common to find it difficult to get WE placements.