20. Why isn't the rock used which is more in keeping with the setting?
Rock armour is primarily reliant on its mass to stay in place, so very dense rock like granite which is available in suitably sized pieces and will last a long time tends to be used.
We can ask the consultant for the next stage to consider whether there are other types of rock which can be sourced which may be more in keeping, but typically the geology in this area is quite soft.