All this will do is kill a certain proportion of UK porn websites...
My point is that shutting down porn sites (following the rules or otherwise) isn't the goal. In fact, if I'm right about it being more about revenue than anything else, shutting down these sites runs contrary to the actual goal - because a shut down site can't pay a fine. Crusades like this never produce real results - there may be an "example" or two made in the beginning, but that's just more about continuing the program and keeping a few thousand overpaid bureaucrats in a job - i.e., making sure the funding keeps on coming. Fines and tax revenue make sure that gravy train never stops - so in the end, it's just tool for channeling all real money to the ruling class. Jerk off to your silly porn all you want, peasant.
If the government really cared about shutting down porn sites, they'd just shut them down, and no, it wouldn't be impossible. If GHCQ and the NSA can record and archive every single voice call in the developed world, and build a search engine for finding single phrases in those calls at will, then they know damn well what you're watching online and whether or not it's "legit" or not. Similarly, making porn impossible (or so difficult as to be utterly impractical for all but the most die-hard) to obtain would be relatively trivial.