I don't know if this is the case now, but when I was looking at universities, I noticed that most universities said that Further Maths was desirable, and helpful to an application, but not completely essential. Though the entry requirements were high, I think most universities wanted an A or higher in Maths.
As I said nowadays it may be different and that FM may well be a requirement. But even so, there will be universities out there that don't require FM for Maths.