Phil Rose: The original materials would be true to the original design. Unfortunately, they have proved to be insufficiently idiot-proof, so I think we would need something that is fire-proof, or at least fire-resistant. It's possible to get cladding for buildings that looks like planks of wood, but is made of lightweight concrete or some kind of similar composite. I don't know whether that kind of material would be suitable for the thinner and finer parts of the structure - specialist advice from an expert would be very helpful.