I would not over engineer a deluxe mews until you know more about what you are doing and more about what you want. It is easy to over look what is important to the hawk and focus on what is important to you, and then you have wasted a lot of time and money. I suggest you build a simple 8 X 8 mews of a modular design with a solid wooden floor that you can easily take apart and move. If you are like most of us you will end up moving it a lot. As for a kestrel I don't know what the rules require but too bad you can't just keep it on a perch in the house because that is the best thing.