My Peaches and Waffle are fans of mud and water. If there is something really stinky somewhere in a field Peaches will find it and roll in it. So there are a few in-between-groom baths in this household.
Here are a handful of the products I find myself reordering as they seem to make my two smell nice and clean.
I really like the Animology range; especially the Fox Poo variety! I still use the Puppy Love shampoo as well as I love the smell.
I also used this puppy shampoo quite a lot as it was really gentle on their skin.