Toilet training an adult dog?!?

Asked: Toilet training an adult dog?!?

Me and my family have adopted a 4 year old female cocker spaniel (we have had her for 4 weeks and started toilet training straight away). She had never been toilet trained as she was rescued from a puppy farm, (She was one of the mothers producing the puppies). She is constantly going to the toilet in the hallway, even when all the doors to the garden are open (we have shown her that she can go in and out of them).
We take her for a lot of walks, in which when she goes to the toilet we say the word 'toilet' and then praise her.
We physically take her outside into the garden when it looks like she wants to go to the toilet, but she still goes to the toilet inside the house.

Does anybody have any good toilet training methods i could use for my ADULT dog.

Thanks, much appreciated xx