I was able to miraculously find myself an herb lady in the CWB wet market with the help of Google Translate, and lots of confused smiling and pointing.

Head into the "main" market building, up the small ramp/few stairs and turn right. There's a lady at the far end who keeps a fridge of fresh herbs, and even a laminated set of english translations and pictures of veggies (hurrah). I have been able to buy some fresh basil and thyme from her at excellent prices.

Now my secret is out, don't be greedy and leave some for the rest of us.