Anyone know if channel drains are available anywhere? Also known as trench drains. Very grateful for any tips.

Alo known in the uk as aco drains i tried for a long time could not find any got promotional material from aco gave local firm they made some for me they worked fine and not expensive

Try contacting Aco Australia as they may be able to put you in touch with suppliers of their products in Thailand.

http://www.acoaus.com.au/index.htm

colinneil, you say you had some made by a local firm.

Did they form the 'U' channel in concrete and fabricate some form of steel mesh grating? I'd be interested to know and it would be great if you could post a photo.

They are made to order on site for most homes by any concrete contractor. I have not seen prefabricated but have not looked either. Most are made with concrete covers for homes (to keep leaves out) except when spot drainage is required and they fabricate metal coverings.