Thank you for all the advise there are some interesting Ideas..
I'm happy that it isn't a health issue and just the fact I now have a white budgie with a dirty brown face and tail and wings!
I tried the lovely warm mist bath. One little mist and he flew off, he is very tame so he doesn't get affected by me keep trying to give him a little mist, he thinks it is a game! as soon as I pick the misting bottle up he flies away I go over to where he has landed he steps on my finger I go to mist and he's off again, he even lands on my back between the shoulders so he knows I can't get him
I put the mist bottle down and he goes on my shoulder, I'm glad he can't laugh because he would laugh at me he thinks it's a new game.
When I put his bath onto the cage door I put warm water in there and only leave it there for about an hour, he just uses it to have a drink,
But the mirror and toy idea I will try and also leaving the bath there longer, I normally take it away as the water goes cold. I will try the lettuce idea. I will try again tomorrow.