As others have said what on earth was Starmer thinking? What qualities does he posses that made Starmer over look his obvious flaws? Does he have the negatives?
The Ambassador's role is really to be the messenger boy for his government so most senior civil servants could do the job. With communication technology I rather think the role has diminished from say pre war. After all why talk to the monkey when you can speak to the organ grinder.
Labour are trying to say the yanks loved him and he has been doing a great job on trade. I rather doubt that, the donkey work is done by Foreign Office staff. I can't see Mandy getting familiar with the minutia of UK versus US farming.
The new guy is a career civil servant, he's probably wondering why he didn't get the job in the first place.