TBH, from my experiences, references for university applications were pretty useless. I handed references in to all of the universities that i applied to before and at interview. From my knowledge, they were never looked at. I was never asked about them at any of my interviews, nor were they brought out at interview with a copy of my ps and school references.
Most universities make their choices for interview by looking at your predicted grades, your ps, your bmat score and your school references. You will almost certainly get asked about your work experience placements (what you saw, learned, etc) unless you apply to Cambridge (who are interested solely in academic ability). A reference shows little or nothing other than you're a nice person who turned up smart, was polite, etc. They will ask you questions to ascertain whether you were actually there and how much you learned. That is what they're interested in. And from interviewing you they can ascertain what your communication skills are really like and what type of person you are. They don't need references. Unless a uni specifically asks for references, or you want to give yourself some more work, there is no need to get loads of references. Simply providing a name and phone number of your employer is normally enough if they want to do some digging.