There was a possible Kat Dennings sighting last week: http://princehals.tumblr.com/post/36...rld-set-update
Edit: And Kat Dennings reported herself in London on the 22nd: https://twitter.com/OfficialKat
The cast is said to be done with the work at Greenwich University (where the above link was). There may be sound stage work yet.
It's kind of confusing, though, because 2 Broke Girls is still taping (in LA!) every Tuesday. So is Dennings getting on a flight on a Wednesday, filming on a Thursday, Friday, possibly on the weekend, flying back Monday to tape again on Tuesday?