What is this hypothetical situation, because if it's a hypothetical of this fight then at the minimum range of six feet there is no way my character is over-extended, nor would it matter as your character came forward into the attack, essentially weakening his own defence against it in order to try for a grab. 

Anyway, I think we can continue with this, because what I've established is that Brennus is in a position where Florian has weakened his only defence against having his head bonked with a wooden sword in order to try for a grab (which I also don't understand, because my character has two hands on his sword I fail to see how even managing to grab one would aid him in anyway)