Your welcome, glad you like the post.
I guess the more accurate name is purple Chinese cabbage as it looked like this but in purple, its the ones standing behind the purple cauliflower. They definitely tasted sweeter than the normal ones, and had a bit more texture and crunchiness.
The hotpot was highly recommended to us by another diner there as we were in two minds about having a hotpot for lunch, but we're glad we listened to her recommendation.