Bristol doesn't teach PPE!
At Bristol, you can do a degree in any one or two of those individual subjects, Philosophy, Politics, Economics, but not a combination of all 3.
Universities with highest entry requirements for PPE:
UCL
Oxford
Durham, LSE, Nottingham, Warwick
Edinburgh
Queen's University Belfast, Exeter, Manchester, Sheffield, York
King's College London can be rather leftist so it requires lower grades from international students than all those universities yet requires the same grades as the top 3 tiers from UK students.