Apparently he's had enough of the transatlantic travel so doesn't come over to the UK any longer. I presume it is still 'his' company, yes.
It is frustrating to want to know what has happened to someone and not be able to find out, especially if it is felt that something untoward might have gone on. It's human nature to be curious but isn't it strange how there is no information about his departure?
Don't think it was just retiring as they would have made a bit of a do about it - Julia would have produced the obligatory cake.
He left the studio a few times prior to not appearing at all, if you remember there was talk of excess refreshments taken!