There is a new coffee bar with Square Mile coffee, 3 group La Marzocco (well soon, he got a 2 group temporarily I learned) and tripple basket option for us addicts on Long Lane by Smithfield, central London. I had a double espresso and a double ristretto (I didn't know about the tripple basket...) and my gf had a cappuccino - all excellent! Oh this is a happy day, as I live in Barbican and this is my nearest cafe!
If you make it a trip to go here (any day but Sundays), further down on the same street there is a gallery/record store/cafe/bar Pure Groove, and behind Smithfield there are a few noteworthy places like Kurz and Lang german sausages, Smith of Smithfields that have potentially the best burgers ever, Vinoteca wine bar, St Johns Food and Wine doing "whole animal cooking" - not to mention the Barbican brutalist grade II listed estate and culture centre. All within a few minutes walk of each other.