So... I put the bearings from the top cup into the bottom cup and vice versa which shouldn't really matter as they are the same size but I just wanted to try every option possible.
Then I had the idea of opening up the metal compression ring as its quite flexible, then tightened everything back up again, and it seems to have improved things. Not saying its perfect but it is better.
Would still be nice to have some input from someone who has ridden their bike after fitting these headsets to see how they hold up under use.