Your second part is not true. As the blog post makes clear, Uber cars drive under the license of a minicab firm (as personal hire vehicles), and are therefore exempt from the congestion charge.
Given your first point, could you please share the like-for-like data on uber vs. black cab time spent waiting to be hailed/booked? That sounds very interesting.
Given your first point, could you please share the like-for-like data on uber vs. black cab time spent waiting to be hailed/booked? That sounds very interesting.