When I look at http://www.bbc.com/news/election/2017/results/england (the election results for England specifically), it shows a comfortable majority for the Tories (297 of 533 seats = 55.7%). Am I misunderstanding something?

This isn't quite accurate.

On such bills there is an additional phase in the process where the English MPs can veto the bill, but they must also be voted through the full parliament.