4th A-level

I am hoping to apply to study an Engineering degree (still undecided) in Imperial College London and have chosen Chemistry, Physics and Maths. I am considering taking a 4th A-level to increase my chances because I only recently made the choice to do Engineering and I would be against others who have had a passion for the subject their whole life so I have less experience. I am undecided between Spanish and Further Maths. I got a grade 8 in both Maths and Spanish at GCSE however I felt it was a bit harder for me to do well in Maths and slightly easier in Spanish but i needed 1 hr weekly extra tutor sessions. What do I need to know before making a final choice?

I am hoping to apply to study an Engineering degree (still undecided) in Imperial College London and have chosen Chemistry, Physics and Maths. I am considering taking a 4th A-level to increase my chances because I only recently made the choice to do Engineering and I would be against others who have had a passion for the subject their whole life so I have less experience. I am undecided between Spanish and Further Maths. I got a grade 8 in both Maths and Spanish at GCSE however I felt it was a bit harder for me to do well in Maths and slightly easier in Spanish but i needed 1 hr weekly extra tutor sessions. What do I need to know before making a final choice?