I was gonna say, there will be a lot of different English Postgrad courses and it could be that Jack went for a really competitive one.Acceptance rates vary from course to course. Although they are on average higher than for BA programmes and PhD programmes, some courses are more competitive. The English literature MSt 1900-present has on average 193 applications and 65 places; the English and American Studies programme has 60 applications and 8 places. So even if highly qualified people apply, some won't get a place. Someone like Jack Edwards or Ruby would then easily miss the boat. Ruby is actually safer in the Victorian programme she's interested in... But even there, 18 applicants on average don't secure a place, and she could well be one of them.
Good luck with the exam!
I do think that Ruby will go for something very impractical, and that will increase her chances of being accepted. Programmes that point clearly towards careers are going to be much more attractive overall as they look like they have better odds of paying off the investment.