Oxford brookes admissions

Hi, I have an offer for Brookes for motorsport engineering in September. My offer requires me to achieve 112 UCAS points as well as a B or above in both Maths and Physics. Brookes website states that if I confirm the offer as my firm choice, I will be accepted even if I miss one grade. Is there any possibility they could reject me if I was to achieve an A*/A in maths and a C in physics? I don't want to rely on this claim just in case they can turn round and say no. Many thanks