It is likely they didn't comply to generate a reaction like many of the comments in this thread.
Calling BishUK an educational site is how this story even broke daylight. The term Educational site is very misleading in this context IMO. I suppose that you can call hardcore porn educational as well though (if you learn something from watching it then you were educated right?).
Traditional "Sex Education" in school is all about discussing the basics of how anatomy works and the responsibilities and consequences that come along with sexual activity.
BishUK appears to go much further. Discussing in detail sexual positions, techniques ETC. Hardly what most people think of when they hear the term "Education" and hardly appropriate for kids.
I find this hard to believe since Justin Hancock, who runs BishUK, claims to not have been aware that his website was being blocked until Newsnight alerted him.
If you are right, then perhaps he got some kind of form email alerting him of this possibility and assumed it was not relevant to his business?
That's nonsense. Every ISP is implementing its own system, and none of these systems include a way to check if your own site is blocked. So, even leaving aside the question of why website operators should be having to plead with companies to let users access their sites, who, exactly, are they supposed to apply for an "exemption" to?
I'm so far unable to find content that I wouldn't consider very much okay for minors (the 'What the hell would a 3 year old do on the net?' question from a sibling still applies). It's a wall of text and weird cartoonish videos/images, paired with the sexual education pseudo FAQs that you get if you buy a teenage magazine over here.
What adult content, on this site specifically?
Glossary:
Adult as in 'of age', legally responsible for himself. 18 for now
Minor as in 'anything below, from 17 downwards'
(And really, show me a 5 or 7 year old kid that would actually look at this site for more than 2 seconds. If you show me that kid, I'd say you can start talking about the content and drop the bee's talk)
If parents want to "protect" their children from porn they should set up filters themselves, or just opt out of the internet entirely if they are unable to do something that mundane.
It's not like their kids are getting strapped to a chair and forced to watch pornography.