Any details of where to find these? 
Any details of where to find these? [/quote]
The internet is lousy with them.
Oh yeah, wow I put “learn to scuba and teach English TESL courses in Thailand” into Google and got 3400 results! 
wow.
So, the better question would be to ask “Can anyone suggest a reputable company?”
There isn’t one - they’re kind of a joke. They’re a tremendous way of making money out of the young and dumb, that’s all. Unaccredited courses that cost about £200 less than accredited ones, in a country with a low cost of living. You might pick up some useful info, if it involves enough teacher observation.
It’s always better to do one in an English-speaking country, if possible, because your teaching practice will be with multi-lingual classes.
If you choose something that’s not accepted in your home country, you’re ruling out ever having teaching as a way to earn money if you ever have to go back, if that’s ever likely to be an issue for you. The Thai ones aren’t necessaril;y a bad idea if you are going to live in Thailand forever, though. They won’t get you far with immigration, nevertheless.