I guess he was just in the USA shooting House. I don't think he went back to the UK. 'Cause than he would visit his friend Stephen Fry and he didn't do that 'cause Stephen Fry would put that on his official twitter account. So I guess it's just a rumor.
About His Lordship supposedly being in Лондон very recently. If he was that is significant, because, if he IS getting divorced, they (Hugh & Jo) could have come to a settled, he would then have had to appear in court on a certain день for the marriage to be declared Decree Absolute. Divorce Granted! I am not saying that IS what happened, but until we know if he was in Лондон and what for, I offer this explanation. AND if infact it IS so there is NO way Stepehn Fry will utter a word, because that will cause a frenzy as to why His Lordship was in Лондон and for such a short time too.
With the schedule that he has right now I don't think he would have been traveling to the UK. Taping House is a 12-16 час день job. He also has the "Emmys" coming up. I just don't see how he could keep that vigorous of a schedule.