Well, after Marius, your general is regular cav. Horrible cav, I had a Egyptian Cavalry General get ahold of a unit of my ELC while they were climbing a tower. Meaning my guys weren't braced for an attack, and the whole unit was not available. The ELC still won. Since Egypt has archers, whereas Britannia does not, you don't need Chariot Archers. Chariots are by no means a necessity if you are concerned about realism.