David Axelrod is really earning his crust from Labour, telling a book-promoting interview that he’s retiring from campaigning: “I’m not going back on that circuit. It’s exhilarating, it’s addictive, but it’s not good for you. I’m done”. With his comments picked up by the Sun this morning, and sure to wind up already tetchy Labour MPs, Guido has crunched the numbers. Today it has been 90 days since Axelrod even bothered to mention his star British client on Twitter. He was reportedly in London for a brief visit in December, but is embarking on a book tour around the USA for the duration of the British election campaign. Worth every penny…