English requirement for BC application

Dear all
My son is 18 years old, and is a first year student in one of universities in London. He has passed Life In the UK test, and gained C in English Higher awarded by SVQ. My question is: is English Higher qualification equivalent to B1 CEFR?

Guidance mentioned ESOL SVQ level4,5 or 6 is equivalent to B1 CEFR. I feel English Higher qualification is even better, but this qualification is not mentioned in the guidance. Any advice please? Thank you.