Coolant flush

What is the best method of flushing the coolant. So far I have removed and cleaned expansion bottle, removed both radiator hoses and flushed through. Every time I fill it back up the water is just as orange as before. Am I going to have to remove the thermostat to flush that side? If so is it a thermostat inside the housing allowing me to remove the stat and replace the housing to rinse it all round?

Matt

there is a coolant drain plug on the front of the block

Excellent, I will look that up