Hello Will,
I am sorry for the delay of this reply.
I've checked your cronjob command and I've made some modification on it. But since the minimum interval offered by your hosting provider is 15 minutes, it's hard for me to instantly know whether the cron is running properly or not.
After some observation in your easydiscuss email activity area, it seems like the email get processed for each cron interval. Can you verify it for me?