Yayyyy I love seeing picture of Oliver!
You guys have defiantly improved! The pictures are kinda hard for me to critique considering they are pretty small.
First you need to look up, and sit back. Relax into your seat bones.
Your arm position looks good for the most part.
Try to relax around your horse. Thinking about this has helped me SO much. I just think relax my legs down and wrap around my horse.
That seems to be what sticks out to me the most, just keep working the hind and you guys will look great!