You only mentioned china, where they don’t report on land costs because all land is state owned but yes I do believe land compensation is much less in china, not least because HS2 land compensation is significantly above market rate. Also; an authoritarian regime with only superficial regard for the health and well-being of their workers, that are paid almost nothing is certain to be cheaper. Suggesting otherwise is banal.
Edit to add Troll alert.
I’ve only got two decades of civil engineering experience in Europe china and now the uk to draw on. I can’t provide a source for the absence of Chinese reporting on land costs because you can’t prove a negative. Although it should be blatantly obvious that comparing the cost of building something in the uk to the cost in china is simply pointless. Here’s a link to a high speed train collision in china that killed a heap of people: https://en.m.wikipedia.org/wiki/Wenzhou_train_collision And another one: https://www.cbsnews.com/amp/news/high-speed-train-derailment-china/ … and a link to construction labour deaths https://clb.org.hk/en/content/china’s-most-dangerous-industry-getting-more-dangerous
The point being that china has a very different equation when they go about doing things to here in the uk.
Frankly I shouldn’t have to do this for you.
You’re supposed to be providing sources about how the land was forcefully purchased at a low and unfair price. Not that trains derail.