Thanks - it is the bloom that I feel is the issue - how do I reduce the effect.
You can't. You either turn if on or off.
In P3D, bloom is controlled by HDR and it's more visible than FSX, so we had to find a setting that would look reasonable both in FSX and P3D.
About your comparison between KORD and KLAX, they use different ways of making runway lights, KORD is default, KLAX is custom. Again, there's nothing wrong with your KLAX screenshot, and in reality a proper effect might be something between default and custom, since default lights are far too dimmed and if I had to choose one, KLAX is way more realistic, even if it's not perfect.
But as I've said, if you don't like the effect, you can turn off bloom HDR.