I tried Nineteen Ten at Westfield the other day. I agree with another poster that it was not so good. Of course, any burrito in England at all is to be celebrated like it's Cinco de friggin' Mayo, but it was not nearly as good as the Islington places. The fillings and tortilla weren't hot, and the salsa was somewhat bland. They also charged extra for various ingredients (like guacamole) but then proceeded to give me what I can only assume was a child-sized dollop of a portion.
I'd eat there again, but definitely not my first choice when it comes to London burritos.