The first link from google gives a full overview of the case: http://kb-law.info/wt_dev/kbc.php?decision=172&&land=UK&lang=EN&page=UK
From the link you quoted the first line from...
"There is no official statutory provision offering 'in the public interest' as a defence to copyright infringement. However can it be used?
The answer is yes but only in very rare circumstances can/ does a Defendant raise these grounds in order to avoid successful action for copyright infringement against them.
Lion Laboratories v Evans - this case saw the publication of an internal memo which criticised the accuracy of breathalysers sold by the claimant. The defendant raised the public interest defence on the grounds that investigations should be made regarding the accuracy of the equipment to avoid incorrect readings when used by the police on motorists.
The three members of the Court of Appeal all accepted this defence."
The article then goes on to discuss how case law shifted one way and then back since, under the impact of various new legislation.
If you're expecting an essay from me to refute Simon's contention this is about right to roam, I'll decline the invitation :)
Don't be lazy. Create a coherent argument providing tangible evidence or stand down. Erm, no? Happy to provide the names for you to do your own reading though. It's a bit more than right to roam but whatever.