Slitherine

In the picture above the 6 man LH facing down the table want to charge the LH just in front of them but they are disrupted and so need to pass a CMT to charge. They do so. Their player wanted to charge my LH only, but I said as they had passed a CMT to charge this also allow/forced them to charge the cataphracts to their front by staggering forward 2".
Am I correct in saying that they MUST make contact with the cataphracts or only that they MAY make contact?

You were correct.

The releveant bits are in Declaration on charges:

Any enemy battle group in the path of a charge counts as being charged if it can be „legally‟ contacted, even if it was not one of the originally declared targets of the charge.

and

If a CMT is required to make a charge against certain troops, it must be taken if required for any of the battle groups that can be „legally‟ contacted in the chosen direction of charge, including by stepping forward bases.

The confusion perhaps arises that there are two reasons that a CMT is needed; disruption and light horse charging proper troops. But once the unit decides to charge, they don't care what they are charging.

I moved this to the Rules subforum as being more appropriate.

Marc