A few developments in the burrito world in London of late:

BENITO'S HAT is now a chain with a second place just opened on New Row in Covent Garden.

MAS BURRITOS has opened up right around the corner from the new Benito's. I have not tried them yet but early tweets have not been particularly positive. They have another site in town but I'm not sure if that's open yet.

MEXICAN EXPRESS is apparently "about to launch a chain of Mexican Fast Food restaurants in several locations around London". Not much known about this other than this link. With thanks to @JonathanMathias on twitter.

WRAP IT UP has opened a new place on Villiers Street between Charing Cross station and Embankment tube. They do a mixture of wrap type foods including burritos and roti and have been trading opposite Liverpool Street for a while. I don't expect the burrito to be good as a result of what seems to be a lack of focus. Maybe I'm wrong?