Found this scenario doesn't work well and is confused. Improved it by removing the Samnite Auxilia and replaced them with a single line of 5 medium infantry (Samnites were recorded by Roman authors as fighting in a single line and lacking reserves) and replacing the light and cavalry units for a single medium cavalry unit (Samnite cavalry are typical Italian cavalry but not numerous). The two Campanian (Roman) heavy cavalry units are replaced with a single medium cavalry on the Roman left. The wood in the centre of the table was removed (no evidence of this in the sources) and the light infantry unit returned to the Roman battleline. After these it played out excellently and very even as historically it should be.