My partner and I tried The Heron yesterday. What an oddity!
It's in the basement of a pub by Edgware rd. The food *on the whole* was delicious -- real deal Thai street food, as I remember it from my travels to Bangkok. There are absolutely no orientalist decorations; no elephant statuettes, etc., -- just a couple flatscreens showing Thai MTV and Karaoke. It's an outwardly cosy and unpretentious setting.
But here comes the down-side. The waiters are clueless and horror show rude. Example: "next dish!" was how the waiter snapped when ordering, and "do you want it or not?" when offering dessert. The coup de grace, however, was the steamed seabass in lime and chilli (which is pictured above). When they brought it out, atop some flaming silverware (it did cost £20 afterall) carnage ensued. They used one two many paraffin candles under the dish. Within minutes a blazing fish-shaped inferno licking 5" above the table had us both fleeing our seats. The other diners froze. The staff rushed to our table with a bundle of dishcloths. And as one lifted the fishy bonfire the other retrieved a candle into a porcelain bowl with a spatula. The lifter then backpeddled, splashing liquid fire over the table, the seat, and on the arm of a woman at the next table. Every one was silently aghast. We looked on as a puddle where our fish was burned. I asked if the woman, now stroking her arm with tissue paper, was alright? She nodded awkwardly. As the puddle eventually self-extinguished, the staff returned with our fish. No apology, just a "leave it or lump-it" silence. Eventually we settled back down and I went for a slice of the seabass - raw, completely uncooked!
Try them if you dare!