Thanks for the answer MartinG, this is what my son and I discussed. Cavalry letting themselves be charged by infantry CAN counter charge but the infantry, as the chargers, hit first. Potentially very painful for the cavalry who will probably lose bases before they have a chance to hit back, ouch.
However, as a retired member of Her Majesties Lancers, I am well aware that the role of the cavalry is to stop the field turning into a horrid brawl. If they are stupid enough to allow themselves to be duffed over by a bunch of smelly footsloggers then they only have themselves to blame