Contextual offer criteriaWatch
Check carefully on each website.
Some use definite criteria - home postcode, school attended, in care, BAME etc
Other are much more vague.
For instance - Bristol - you know if you qualify for a lower offer before you apply : http://www.bristol.ac.uk/study/under...extual-offers/
Bath - you have no idea, they say they look at 'contextual data' but they dont give lower offers, go figure : https://www.bath.ac.uk/guides/unders...te-applicants/
Some universities make offers based on whether the school was in the bottom 40% for results in the previous year and both Bristol and Exeter use this. Manchester and Leeds have made offers based on post code. This information may have changed in previous years. As said you need to check the individual university.