I have just phoned around some universities.
They say they class IGCSEs and english GCSEs as equivalent and you must have UCAS points suffcient to qualify you for the course, plus many require IELTS.
A part completed A llevel will mean you have some UCAS points.
I think an interview and application form count for at least as much. They are despaerate for money and foreign students pay more than UK students, so they need a damn good reason to turn you away if you are a foreign student.