Cocker Peeing in His Bed at Night?

My 4yr old male Cocker has started going to the toilet in his bed at night. He can't be trusted to roam free in a room for the same reason so we have him in a soft crate while his brother can be trusted so roams free (laundry). Lately he has started going to the toilet (pee and poop) every night.

We've tried taking them out before we go to bed (they come in about 7pm and I go to sleep about 10pm), but this hasn't helped. We've tried punishment - putting him in the garage overnight - no success. His diet hasn't changed. Our hours of being away from the house haven't changed - nothing has changed that we can think of. We don't mind if they go in the house when they are unwell, but this seems to be willful behaviour. They are usually in the house between 7pm and about 6:30am. Please help!