A change I made to the way hits get counted means search bots will no longer make an impression on stats. They'll still access and index the site as normal, but now we'll see a truer representation of visits per day.
Turns out that code change mentioned above only stopped bots increasing individual topic view counts within the forums. It didn't affect hit counts recorded in the overall stats.
Made a change today that I hope will stop most bots from increasing the hit count. We'll see if the daily hit total goes down from here on.