Hi Natalie,
This is exactly the same as my situation! I didn't do very well in school and now I am in college again because I want to study Midwifery at university.
At the moment, I am doing Functional Skills Maths and English. If I complete successfully, hopefully I will be doing my GCSE Maths, English and Science next and then onto an Access to HE in Health Professions.
Personally, I think it is the best path. You can get a loan to cover the cost of the Access to HE courses and if you successfully get onto a course at university, this loan doesn't have to be paid back.
As long as the course content has a majority of science based subjects, it should be accepted as an entry qualification along with your GCSE's.
Also, have a look into visiting some antenatal classes and maternity wards and write about your findings in your personal statement as this will show your understanding and commitment to doing this course.
Hope this helps!
Michelle