Most people are going to tell you that doing a degree just for job prospects if you're not passionate about it is a waste of both your time and money. Much better to be doing something you'll really enjoy, then see where it leads you knowing you loved your time at university.
I made that mistake by wanting to do a different degree at first, but then realised (thankfully not too late) that I was doing it for all the wrong reasons, and I want my degree/course choice and university to be a reflection of me. Particularly in your case, where English language and Social Anthropology are both arts subjects, where you'll develop transferable skills in terms of communication etc. I really don't think it should matter - especially not if you'll love the content, and if you're at a good uni like Manchester.
So yeah, don't suffer when you don't have to. Plenty of people do a year or so of a course realising it's not for them, and it's just an experience, really - plus, you'll be far more committed and likely to be doing really well once you ARE doing something you enjoy.
Have a word with your personal tutor/the relevant departments of your uni if you wish to stay there and simply change course and go into first year again, or you could take a break from education and start a new UCAS application next year for 5 unis for the course of your choice. Good luck - hope it all goes well for you!