Alan, I love the Suan Lum night market at Lumphini but it is supposed to be closing soon for a new development. This has been happening for many years and the traders there have been fighting it. I dont know what the recent position is but I believe some of it is still operating.
Here are a few photos taken in 2005 of the Food Court and Beer Garden there.
When we were last there in 2008, not much had changed but many of the restaraunts near the market sent touts in with menus to try and get you to order from them instead of the stalls that lined the left side of the market. As soon as you sat at a table you were confronted by 10 people all brandishing menus, some from restaraunts and others from the beer providers pictured. If you want a cheap meal, just politely decline and head to one of the stalls.
The Beer is served in several different ways, one of which is the Beer Tower. If you look carefully at the foreground in the picture of the dancers, you will see a table that has on it a large upright cylinder. This is full of beer and has a tap connected to it and is surrounded by ice. A great idea if there is a few of you.