Perhaps you could get a bigger tray as Freddie looks a big cat and the tray is normal size, experiment with litter, try the Danish Pink or corn litter, not all cat will use the wood.
Wipe everywhere he has peeed/poooood with surgical spirit. Pure orange or lemon essence sometimes helps and the house smells nice too, it is available in quality food shops. Have you had him examined by a vet to ensure that there are no underlying problems? If you see a Homoeopathic vet they may prescribe something like rescue Remedy.Freddie to that room. Most important is that you do not shout at him as very often stress causes inappropriate behaviour. You could try the Feliway spray and leave dried food where ever he 'goes'.