I ate dinner tonight at a place that uses Clover (I didn't think it was that popular in the UK, but there you go). The server even brought over the Clover Mobile for payment, too, and the receipt said "device verified" on it.
BTW, I think nearly every receipt I've managed to get so far this trip has some form of "device verified" on it. ^ Unfortunately, a significant number of places don't give you a receipt for contactless, so I can't 100% for sure say that every store supports CDCVM.