
<<<The other problem is that at night or if we have to leaved him for a couple of hours, we leave a couple of the training mats for him to use. Sometimes he will use them and he gets praised, however, fairly often, he will cock his leg against the sofa or wall.>>>
This may be what is confusing him ??
The fact that you want him to go outside and you praise him and then you leave the training mats and still praise him
He may just associate weeing/pooing with being praised and not the actual place of where he does it .
I would remove the mats at night time and when you go out and see how he is then .And praise if he hasnt dirtied in the house at all
Good luck ;)
Le