Hi There Charlotte, whenever I left my dog, (he used to escavate the plaster walls too!) we just got cardboard boxes and flattened them and placed these against the walls all the way round the rooms he was allowed in, we also used to leave a boiled marrowbone that is filled with a cheese or meat mixutre which keeps the dog working on getting the food out of the middle and its good for their teeth and helps stave the boredom, or buy those huge raw hide chew bones, a dog gets bored because his mind is not active.....also take him for a long walk in the morning before you leave for work and when you return back home....exercise is also a vital factor in a tired dog is less destructive, get up earlier in the morning and take him for that walk !