For the intrepid crew of cypherpunks who are erecting a data haven off the stormy coast of England, making sure the technology works will be the easy part. A more serious threat is likely to be governments alarmed by HavenCo's offer to host individual and corporate sites that are illegal in some parts of the world.
Some countries consider gambling or sexually explicit websites to be illegal.
According to HavenCo officials and the company's terms of service, everything but spamming, obscenity, and child pornography is legal. The company plans to begin operations by September. It depends largely on who this entity's backers are. I suspect we could blow them out of the water, although I wouldn't recommend that, and if they were in fact propagating illegal material I bet nobody would really care. London's Home Office could restrict the microwave links that provide HavenCo with its lifeline to the outside world, and the companies offering satellite connectivity could come under pressure from regulators in their home countries.