We have found that the best way to wash your down jacket is to wash at 30*C, using a small amount of washing powder, no softener or bleach.
For drying, if using a dryer machine, add in tennis balls during the cycle to avoid clumping and improve the loft of the down. You can Iron with no steam, use a cloth between iron and clothing. If air drying, do not hang, must dry lying flat. Gently knead the down with your fingers to break up the clumping of the down.
do not tumble or dry clean.