I took a quick snap of these bollards as I'd never seen any with "CV" on them before. Apparently I'm not the only person who was curious about them. I found a blog post by Andrew Whitehead, who reckons that "CV" is for Clerkenwell Vestry. These are in Northampton Row, just off Exmouth Market. www.andrewwhitehead.net/blog/so-whats-in-a-clerkenwell-cv