It's worth reading the legal web page. It claims the RIGHT to harvest ALL UK-based web content. Which has annoyed one of my clients who, although hosting in the UK, was specifically told, about 15 years ago, he should not trade with UK citizens.
There is an option to block through robots.txt but if that's obeyed then surely it negates their mandate? They also say we can block by IP. Hmm. But then, this is UK bureaucracy, which hasn't yet caught up with modern technolgy - ie later than 1950.
Currently blocked but clients canvassed as to what they want done; though I suspect we will have to comply. :(