Yeah, the programme I wanted to apply to also specified just a 2:1 degree in a related field, but since I hadn't done any specific linguistic study, I was told (by the professor in charge of the programme) that I likely wouldn't be accepted. YMMV. UK unis love (love love love) the exorbitant fees they charge overseas students, so they often overlook lack of qualifications (I say this as someone who has taught pre-sessional courses for non-English speaking foreign students), however, you (the OP) may want to consider whether your background actually does prepare you for the course you want to undertake.