I think this is a perfect example of how maths in the National Curriculum is treated as a set of facts to learn rather than skills to help you think.
From working through the Chinese problem it doesn't seem to require any knowledge beyond that required from the English one plus a few basic facts about angles (which were certainly being taught at KS3 a couple of years ago).
Therefore if a Child who is capable of doing the English problem is also capable of spotting which angles they need to find, which triangles they lie in and what they need to know to calculate that they could solve the Chinese problem without trouble.
If children were allowed to do more investigative work rather than being shown methods to practice on basic problems then we wouldn't have any problems asking questions like this at university level and it would make the subject a lot less dull. What's the point in teaching them all this stuff if you don't also teach how to use it and where it comes from?
As it is, I can just see a large number of students perfectly capable of answering this problem, but being put off by finding it too daunting due to not being put in the position of having to take problems apart before.