further maths A level

I'm a year 12, i was thinking about maths and econ at uni at somewhere like lse or ucl or oxbridge
I saw that further maths was greatly recommended but I have not been able to do it for A levels as though my school offers it, I did not do further maths GCSE, so I was not allowed to take it.
I'm really considering the course but I don't know if my chances of being considered as a competitive applicant are too low that it wouldn't be worth to apply?
For context I did get 10 A* for my GCSE's including maths, and also would applicable to receive a contextual offer for my A level grades at unis that offer it.