Hi! I'm in a similar position, trying to narrow down my options for university courses. In my opinion, your enjoyment of the course is the most important thing. If the only thing that is making you second guess English Lit is the jobs, then I would say do a bit of research but don't overthink it. You probably won't join the full-time work force until after you graduate (so you have a lot of time to figure out what you want or what areas you like), and English provides a lot of transferable skills, meaning that you won't be tied into a specific career. Some people will disagree with me (and you might as well), but that's how I like to see it. There is point in wasting three/four years and thousands of pounds for a degree you only sort of want.
I would also say, it is sort of obvious and unhelpful, but do some wider research into unis. Some won't require maths if you want to do BioChem, and most English courses won't have subject requirements (other than potentially English, which clearly isn't an issue lol). If you do really want to do BioChem at a uni that requires maths, you could always talk to your college/sixth form about staying on a year to do it, or potentially taking a foundation course to make up. There will be a way for you to do whichever course you want to. You also have a lot of time to make up your mind, and you could always apply to two unis for English and three for BioChem, for example. Hope you find something that you love!