i think if any of the measurements were anything to worry about they’d have mentioned to you during the scan or requested more scans. some of them have those little charts next to them, i think you want the arrow in the middle, but again it’s normal for a bit of leeway on these as they’re not always super accurate.
On the sheet they add to your maternity notes from the scan, there should be a little scale for head, leg and belly (abdomen), if it’s in the middle that is ‘average’, anything to the sides shows how the baby measures across percentiles. At 28 weeks it’s all quite early for baby positioning and measurements… in all honesty with my first everything made me nervous as I didn’t understand what was ‘normal’ but second time feels much easier x
At 28 weeks there’s still plenty of time for baby to turn around, so I wouldn’t worry about that yet. You can check out spinning babies for some suggested exercises to help get them into right position. My first baby didn’t go head down until about 36 weeks (and was born at 38 weeks)