Looks good. 40cm is a bit to be losing though, you will never regret going as big as you can (within reason). So if you can wangle the straight hall and keep the living areas the same size, i'd try do that. With the meter in the garage, you can have that installed in the switch board box. Just need a taller one of course. It's what I did in my place, switch board stuff is at normal height and meter is installed above it, all in one neat box.