Well - and I realise this is off topic so please anyone say if they want me to pull this off the thread - Andrew was always more Andrew than Adonis.
Selective schools ( independent or not) are going to get more ( whether Oxbridge or not) more places at highly regarded and selective universities , because they are selective , so chosen the brighter children.
There was a very very interesting post which I cannot find and I wish I could. If anyone knows it - it was an article about a number of tutors discussing who should get a place and one candidate - they said X won't be able to keep up. so sadly we should not offer X a place. I must google this - it was a poignant and interesting article.
Not sure having different colleges is the way to go. I think greater access and information from schools - but there you go ( motherhood and apple pie) I am not a university lecturer nor involved in outreach. But confidence to apply I would say and then some knowledge of different applicants experience. But what do I know.
& by the way I would say that for a great many universities - not just Oxford and Cambridge which make great headline news but do not corner the market in a very very very good tertiary education.