Linkage

Strong results on university participation and ethnicity from the IFS:

... Chinese pupils in the lowest socio-economic quintile group are, on average, more than 10 percentage points more likely to go to university than White British pupils in the highest socio-economic quintile group...
... 34% of Chinese pupils attend one of these selective institutions, higher than the proportion of White British students who go to any university...

This isn't just about Chinese overachievement: White British participation is lower than any other ethnic group, including Black Caribbean.
My best guess as to why would be: migrants are a highly selected bunch. Of course not many of the non-White British in the sample (who were doing their GCSEs in 2007-8) are likely to be immigrants, perhaps not even the majority of them have immigrant parents. Nevertheless, if there are differences in family culture across ethnicities (in the UK) which persist down generations, that might explain what is going on.