I tried changing the class of the bodyguard units to spearmen (and the ones with ranged attacks to missile), which seems to work quite well, didnt test it really yet. The general stays behind their main line until your lines clash. Dont know if changing them to spearmen gives them bonus to cavalry though.

I also decreased their attack and charge value a little, but that doesnt seem to make a difference. Decreasing their charge range might also help, because then its less likely they are the first one into enemy lines.

Giving them 3 HP is too much imo. Especially the retinue of a king (twice as big as normal?) is a tough nut to crack with 3 HP.