One tweak to the rules and all of a sudden not only do porn sites have to verify the age of their UK visitors but also anyone connecting from something other than a residential ISP.
The more troubling thing about these laws is enforcement. The threat of fines only works against websites that map to a business entity. For anything else there will surely see a ramp up in the size of The Great British Firewall Ruleset, edited by the courts, and distributed to the Big N (5?) ISPs.
What will become of the smaller ISPs that refuse to block illegal sites?
I don't think many people object to blacklisting known sources of child pornography etc.
The fact is you now have to verify your identity (name and photo id) in the UK to access an adult subreddit.
This is a red herring for authoritarian tyrants in the UK to get more control over their population, which is all they're ever looking for.