Hi Tony
I know you will probably have sorted this problem out long ago now but I was just going to say we had the same problem when we picked our springer up. Mia came home and she was a dirty yellow stained colour, all we used was a Pets at Home Puppy Shampoo, we still use it to this day and Mia is now 18months old.
We find as long as you build up a good lather of shampoo and really work at her coat, the results are great.
Kind Regards
Dani & Liam