So I visited The Cook today, as I was near the Amarin Plaza anyway, and I thought I'd give it a shot.
Firstly, if you're vegan like me, there are lots of vegan options, although a couple of things do have eggs.
I had a plate of rice with 2 options, which came to 45THB, a little under £1. I chose the thai sautéed broccoli, and sweet and sour tofu with veg. It was really delicious. Much better than what I was expecting. Definitely recommend this place if you're in the Ploen Chit / Chid Lom area, and even if you aren't. A steal. I'll definitely be going back to try more.
Cons: A little salt heavy