"...with 15% international students"
A very long time ago indeed when I went to university, the university I went to had around 95% UK undergraduates.
Today, the university has grown massively and has around five times the number of undergraduates (although it has absorbed some smaller institutions over the years, so the numbers aren't directly comparable).
Of these undergraduates, around 46% are UK, 8% EU and 46% international undergraduates being charged the full international fees.
"(Not so much when the percentages are higher and they are all from one country but that's another story...)"
Around half of all international undergraduates at this university are from China. The next two biggest locations are Hong Kong and the USA.
University education has changed very noticeably over the last few decades.