I agree, no toys, no TV and if you could all sit up to the table together you might find you really enjoy it! Also, eating earlier works in our house, we often eat together at 5pm. Don't know if your OH is home at that time, so if it's possible?

Does your DS eventually eat all of the food you put in front of him? Maybe he eats so well during the day he is full at dinner time and doesn't need as much food as you are serving him?

FWIW, I was a reeeeaallly slow eater when I was a kid. I was always the last to finish my dinner, regardless of what it was or how hungry I was. I really wasn't trying to be difficult, I think I just couldn't swallow my food until it had been well chewed and I didn't like large mouthfuls. We sat at the table, no TV (dinner was a very social occasion and we all talked about our days instead) and I was encouraged to eat if I really slowed down. I know it was frustrating for my mum and often she would start cleaning up before I had finished while my dad sat with me. If he got frustrated, he would eat mouthfuls off my plate while mum wasn't looking! As an adult, I am still a slowish eater and usually the last to finish. I hate that feeling of shoving food in my mouth and swallowing before it's properly chewed. Food should be enjoyed!

So, my advice is no distractions, all eat together, gentle encouragement - and plenty of patience!