[eluser]doubleplusgood[/eluser]
Thanks n0xie. I now know what was going on. I'm using this line to get the user information;
$owner = $this->auth->get_user();
And it was trying to pass all of the information into the array, so it would never have returned a match. I need to pick out the userid from the above line.
Tested by replacing $owner with my userid 10.