Why in particular? Plenty of other registrars offer .uk or the public suffixes under it like .co.uk and .org.uk
The Nominet requirements do cause these to break mysteriously much more often than some generic TLD spun up yesterday by people convinced this is a gold rush (e.g. my registrar offered me a great renewal deal for a .co.uk I control, I pressed "Yes please" and then their system believed I had taken the deal but didn't renew the ___domain, after a few days they confirmed that the deal makes no sense for .co.uk and refunded the money, they had forgotten to blacklist Nominet when adding their deal feature), but it works well enough most of the time.
“Some registries do not allow domains to be registered with WHOIS Redaction or WHOIS Privacy. Many of these are country TLDs (ccTLDs) like .uk. Cloudflare does not yet support TLDs that prohibit WHOIS redaction, but we will in the near future.”
Nominet is a bit of closed-shop with strong links to existing UK-based registrars. I may be too cynical but I just get the feeling that they'd see Cloudflare as too much of a threat?
