UCAS personal statement

I've been reading example personal statements for undergraduate Computer Science degrees at UCL, University of Bristol and etc. Almost all of them mentions having achieved gold certificates or higher achievements in maths challenges like UKMT SMC and Olympiad. As someone who has never participated in any of those, is it possible to get a place in UCL with the right grades?

Yes, it is absolutely possible to get into UCL Computer Science without UKMT or Olympiad awards.
The personal statements you’re reading online are not representative of the average successful applicant, as examples that get shared tend to highlight exceptional achievements. UCL does not require maths competitions and does not expect most applicants to have them, instead, strong grades, particularly in Maths (and Further Maths if available), are far more important. What admissions tutors care about is your academic ability and genuine engagement with computer science, which can be shown through your subjects, coding experience, independent learning, projects, or wider reading (competitions is just one of many ways, it's not the only way is what I'm saying). In short, meeting the grade requirements and clearly demonstrating interest and aptitude for CS matters much more than having competition certificates.
In summary, I wouldn't worry about not having done competitions,
focus on getting the required grades and if possible see if you can demonstrate your interest in comp-sci through some other extra-curricular besides competitions, if you want to elevate your personal statement.
Good luck with A-levels,
Alfred,
Ulaw..

I've been reading example personal statements for undergraduate Computer Science degrees at UCL, University of Bristol and etc. Almost all of them mentions having achieved gold certificates or higher achievements in maths challenges like UKMT SMC and Olympiad. As someone who has never participated in any of those, is it possible to get a place in UCL with the right grades?

Honestly I'd imagine most who get in haven't done any of those? Also there are plenty of other activities you can do to demonstrate interest in the subject besides those anyway.