After upgrading from 4.2.2 to 4.5 all of my settings were removed.
I'm running WP 3.01 with network / multisite enabled. When I move from each site to the other, they all have exactly the same settings, so if I set the twitter user as "pauloflaherty" then it is the same across all of the sites.
4.2.2 worked perfectly fine in the multisite environment.
Downgrading until this is fixed.