I'd mount it higher personally. A bird house wouldn't look correct mounted that low but simply from a camera perspective, you get the best facial shot from straight on. So around head height to slightly above / below is ideal. Most go slightly above just because the extra height adds a little security and pointing down reduces glare.
Looking at your last photo, I'd also raise the question of what you're trying to protect here, the house or the cars?
The 5231R seems to be pointing back towards the front door / windows. That's good but leaves the footpath, cars and garage as areas to consider along with the garden - a thief won't necessarily use the path if they realise there is surveillance or strong path lighting.
Looking at the Google overview from earlier in post #30, you have vulnerabilities along the right side also. Your own picture also shows the garage will mask the view of the cars. I don't really see this as a simple 2 camera set up if you want total coverage. The house shape is awkward to cover given that's it's not a simple square area. I'm personally a great fan of crossing camera views as then each camera protects the next one from any physical interference, although it does often take more cameras. If you were going to use disguised cameras then a birdhouse in the corner on the fence to the left of the garage (when viewed as per google standing from the road), with the camera looking back towards the road, depending on fence height, might provide good coverage of cars / garage and although it would be vulnerable to someone attacking it from over the next door fence, as a bird house, it's probably not going to be a target unless obviously not a birdhouse. I like the position of the 5231R. I'm not so keen on the porch camera or the uncovered area to the right. I'd be tempted to move the porch camera back onto the house under the porch almost like a
doorbell view, so it's covered by the 5231 although it could still be bird housed. It would still get a great view of the path and should be shielded more from the sun. Your drawing shows it at an angle although realistically as a birdhouse, it's going to be square to the wall or porch frame if the original mounting position so that might be an unrealistic view you've marked there. The vulnerable area will the right hand side of the house although the 5231 should cover that side of the porch, just not access to any side window or the rear from up the side. Just some thoughts although I defer to those with more experience here.