" Red brick universities do like a language. But most unis do not require it"
The problem is that there's a distinct difference between "the minimum the department will accept even if you've just published your first novel to wild acclaim" and "the minimum you realistically need to get in given the competition and that you're just this arbitrary applicant".
The huge advantage that children at academically-focussed schools and/or whose parents are involved in higher education is that they know about the latter, whereas other children are left relying on the former. Moreover the schools attended by those relying on the published minima further hinder their pupils' chances by offering all sorts of "ah, well, it's like an A Level" or "well, it's almost the same as that GCSE" qualifications.
So the likelihood is that for humanities you want English, History and an MFL at A Level, with History replaceable by Economics, Maths, Music or something depending on the biases of the course you want to do. For sciences you want Maths, Physics and either Biology or Chemistry, again depending on the biases of the courses you want. GCSEs should include all the sciences, at least one MFL, at least one academic humanity (probably History, maybe Music) plus English and Maths. But at academic schools, this is hardly worth worrying about: that's what people do anyway. The head of a grammar school isn't interested in the siren voices of "this diploma is 'worth' 4 GCSEs" or "Music Technology is like Music but more interesting" because he knows that, for his pupils, it's simply not true.
But candidates who apply to top-flight universities with weird not-quite-GCSEs, not including MFL or standard sciences, followed by not-quite-A Levels or A Levels in almost-but-not-quite subjects are starting on the back foot and probably won't get quite the same grades either. So a truiple deficit: the GCSEs aren't as compelling, the A Levels aren't as compelling and the ultimate grades won't be as good.