2 Year Old Male Staffy Peeing and Pooping Inside?

Our 2 year old Staffy has two walks per day and has access to the garden in between times. Most days he cries early in the morning between 4- 6 am and I let him out for a pee, he is rewarded with praise and a piece of biscuit.

It is not every night, but he pees and poops in the kitchen.
I have taken to sitting up till 11 pm to let him out for the last pee before bedtime.
He has access to most of the home as we live in a bungalow. And at times he pees up furniture, we do not see him doing this. At times he goes to the backdoor in the evening and cries and I let him out straight away, he is always praised.
I have used the sprays to deodorise where he has been to no avail, it is not always in the same place. He has not had his testicles removed.
He has never been smacked, but told off sternly.
When he has done this he cowers and won't enter the room, we are then made aware that he has urinated.

By Janny