Nice restaurant offering Southern Thai food near Wat Salawan. Try the Kua King, or Gai Ruen Khem. Open from early to 8 pm. It’s called KRUA PAK TAI which means “cuisine of the South”. The owner is from Nakhon Si Thammarat.
Here’s the google map location: https://goo.gl/maps/DuXV9vGjAZC2