Moving into year 13 focusing on 2 do the other during the gap year

Hiya, I’ll be moving into year 13 however my grades are VERY low due to ALOT of procrastination and personal life issues I’ve experienced and I’ve lacked summer revision due to a long a apprenticeship/holiday abroad. My college suggests for me to re take the year. However, I don’t want to sacrifice my gap year. I was thinking if I could just focus on 2 subjects I’m strongest at. Then retake that subject I didn’t revise for during my gap year independently. In the end I’ll be in the same position either way without sacrificing my gap year.
But would my school allow this or is it against their interests most likely? Or is it just better to retake year 12? Will I run into any issues if I do this?
Subjects are: Maths,Comp sci & psychology

Would you be able to resit Year 12, do Year 13 and then take a gap year?

Hiya, I’ll be moving into year 13 however my grades are VERY low due to ALOT of procrastination and personal life issues I’ve experienced and I’ve lacked summer revision due to a long a apprenticeship/holiday abroad. My college suggests for me to re take the year. However, I don’t want to sacrifice my gap year. I was thinking if I could just focus on 2 subjects I’m strongest at. Then retake that subject I didn’t revise for during my gap year independently. In the end I’ll be in the same position either way without sacrificing my gap year.
But would my school allow this or is it against their interests most likely? Or is it just better to retake year 12? Will I run into any issues if I do this?
Subjects are: Maths,Comp sci & psychology