If he agrees with your broad philosophy on life, winemaking and the importance of giving young blokes a bit of a go, he says "yep!".
If he disagrees about the state of the nation or your approach to arrangement of barrels in the barrel hall the exclamation is invariably "Nope!" "What-The" is reserved for those extremely rare occasions where he is genuinely caught short of a "Yep" or a "Nope".
You can probably deduct from this that Mark is a man of few words. He is, in fact a man of action....when circumstances require. He is capable of doing the jobs of ten people half his age while he works his way up to another "Yep" "Nope" or "What-The" He is Bloodwood's philosopher in training..all he really needs now is a couple of large white standard poodles and a map telling him where other people think Vienna is. It won't be exactly there of course, and the spelling will be all wrong, but that, too is a problem Mark can fix. Like that other bloke philosophising around a few words like "will" and "life", he is an unattached late bloomer. And about the best friend Bloodwood has ever had the luck to encounter. Opposites, you see, do attract.