Why would they inform him? I don't follow.
I believe he moved premises because his business was failing and he had leased very expensive premises which are now too large for his ue - due to loss of staff and listings.
So he's moved to serviced offices which is much cheaper, and more of a relevant size. He gets a receptionist who answers the phone and can screen calls, office equipment and facilities, and can manage his rent roll and a few listings from there. Dealings with clients can be done there too, or he can go to them. It would basically be just scaling down to what is practical, to try to keep afloat IMO. But I don't think it is related to the case itself in particular, he began moving out of the other premises a couple of days ago before the toxicology report was out. I would suggest he would have organised these new premises last week.
Either way, why would police advise him of results? He is most likely a suspect. And no, I don't KNOW that he is, but it is highly likely IMO. Just because they haven't announced it doesn't mean they don't have a suspect. It is all about building a case with the least amount of interference and not giving the murderer and accomplice/s any additional help to either weasel out of it, or to corrupt the case in any way.