Thank you Jon,
I didn't consider Traffic Global to be the problem because it causes no issues at any other locations at the current settings. However, I have to reduce the density to 25% to eliminate overlaps at EGFF.
That does not completely resolve the issue. With the Cardiff Mod left in I still get a couple of issues (Pics). Removing the Mod gets rid of those.
But removing the Mod also gets rid of the airport ground traffic, the airport is then completely lifeless apart from a fuel truck and car in the GA area.
Disappointing for a payware airport but I guess I'll have to put up with it.
Regards,
Steve