I didn't have a good camera with me, but attemped this stich shot to try and show the scale of the sinkhole. You might just see the 4 people standing on the rock in the distant cave mouth.

Great. Can you give a location?

Hi Jon, this is near Getu (??) in Guizhou, China. I've got 25.677553, 106.280771 for the sinkhole using Google Earth, but China uses an offset so that's probably only good for finding it online. Access is by a 4x4 track from Xiabayang (???).
The shortest way to the bottom is a 150m abseil with 3 bolted anchors. We bolted a 200m climb on the smaller of the two main walls, starting just above the small (relatively) cave in the wall near the centre of the picture.
Here's a blog post about our trip there which has some much better pictures than mine!
https://www.gokunming.com/en/blog/item/3893/getting_away_descent_into_a_giant_guizhou_sinkhole

Apparently UKC changes Chinese characters to question marks.

Thanks! I look forward to reading all about it. Looks like a proper adventure.