Interesting. I had been misled by popular articles calling them the Chinese species, but looking more deeply the papers detailing the original ultrasonic studies at Moscow were indeed with the Vietnamese species but then further studies were done in China (on Chinese species) and the popular articles were merging information together.
That's my mistake, the label on the enclosure clearly says T. cinereus (and a male for what that's worth!) and I'll change the name accordingly. However very interesting that it's more complicated than that.