my 2p.
If you're off sick then you're off sick and no way should you be sitting in a pub anywhere!!!
Unless you're doing a day of seeing how you get on, out and about, preparatory to returning to work the very next day, you should be at home.
Is she self-certificating or has she now been off long enough to have to go to the doctor to get a sick note? If so, does she have her doctor under her thumb?
Either way, sounds like your HR need to get involved and some serious verbal/written warnings procedures need to be started.
Jackie, Peer Moderator
www.iqps.org