Mature student entry requirements are rarely published in detail, as they're decided on a case-by-case basis.
My best advice is to contact the Admissions Office of your target unis, explain what you're planning and ask what they want from an applicant in your situation. It would be gutting to do all this study, only to discover later that your unis want something different. Never try to second guess them - different unis may have different requirements for courses with the same name. Some will want a particular 'flavour' of Access course. Most unis these days will also want GCSE Maths and English at Grade C or above.