Louis had/has ear mites, the vet said its quite common in puppies that haven't yet started their advocate treatment. She said cats are the worst culprits for spreading them, she asked if we have cats in the garden which we don't have many but I noticed one a couple of times before we picked him up. Also he was playing with one at the breeders when we got him.
He had been on drops when we went back for his second shot but they hadn't quite cleared so hopefully the advocate will have finished the job. I have to try and do his ears when he is asleep though as he is not keen.
It's also quite difficult to clean them, can only really get to the outer ear but when the nurse put the ear light in it goes deeper and came out covered in gunk. Hopefully the gunk works it way up the ear.