I gave him a 30 minute ban with a message which included his KD (250%) and requested him to crank it back. I followed up by verbalising that anyone I banned in this way who does not conform can expect a week's ban.
It appears that week has come somewhat more swiftly than I anticipated. Let the week expire, then watch him like a hawk. Give him one warning and then go Perm if he fails to comply.
Well spotted and many thanks for being one of the Admin's who takes his responsibilities seriously, you're in the (with a few exceptions) minority!
Never interrupt your enemy when he is in the middle of making a mistake.