Hi James.
Yes it sound like you are not getting round to blind enough. On flat water you can land OK without getting all the way round because you can spin the last bit on the water, if you are not all the way round. When its choppy doing this can often trip a rail. Commitment is the answer. Pull harder to blind to get a faster rotation, so that you turn more than 180deg and are landing going towards the kite, with you weight over the board.
Choppy conditions also make it hard to get good pop. Pick your spot to take off from. I find it easier coming into shore between any swell that is running.
Hope this helps