Chances of getting in St Andrews for a Biology or Chemistry degree with a HNC/D?

Hi everyone,
Im a scottish student, currently 18 years old and about to start a HND (but could downgrade to a HNC if i wanted) at a scottish college. Im going to college because I didnt meet the entry requirements for most universities due to having a shitstorm of a year in S5 and leaving school because of mental health reasons after my higher exams. (Therefore I didnt stay for S6). Im doing HND applied science (Chemistry and Biology focused with a small amount of physics) and I was wondering if Id have the same chances as someone applying who meets the standard entry requirements as long as I got an A (HNC) or AA (HND) in my graded units.
For reference, my current qualifications:
7 A's at Nat 5 in English, Maths, Chemistry, Biology, Physics, Geography and Classical Studies.
A- Higher Human Bio
B- Chemistry
B- Politics
C- Maths
C- Physics
Not the best highers, I know 😕

Thanks 🙂