How to become HCPC approved after university?

In order to be a prosthetist you will need to register under the HCPC. I decided after my first year that I want to be a prosthetist but quickly found out that I will need to be HCPC approved but my course in biomedical engineering (and other BME courses is not approved) so what is my next step.

Thank you in advance for all the advice

You will need to take an HCPC-approved masters course. There appears to be only one course available at Keele Uni:
https://www.keele.ac.uk/study/postgraduatestudy/postgraduatecourses/prostheticsandorthotics/
It's a pre-reg masters which means it should qualify for undergraduate funding (both tuition fee and maintenance loans). You would also be eligible to apply to the NHS Learning Support Fund for the annual training grant of £5,000 per year plus other benefits:
https://www.nhsbsa.nhs.uk/nhs-learning-support-fund-lsf
https://www.healthcareers.nhs.uk/explore-roles/allied-health-professionals/roles-allied-health-professions/prosthetistorthotist
https://www.healthcareers.nhs.uk/career-planning/course-finder