Question about ISP address logs in UK?

I think your search will have to be fairly broad, as people reporting on such cases (if there are any) might use synonyms as there might not be very good understanding of the technicalities. E. g. search under not just ISP but "Internet service provider" and "service provider"; search under "cyber crime" and cyber AND crime or cybercrime, etc.

It might behoove you to contact an attorney you or your family may know, too (I believe you want more of a solicitor than a barrister; this is someone who would perform research but wouldn't necessarily go before the bar and argue cases). Of course you don't want them doing the research for you - they'd have to charge you for their time, for one thing - but ask if there are particular law journals or articles that they might recommend.

You may also need to broaden your search to outside the UK, as offenses committed on, say, Singapore soil could potentially be the subject of case law in the UK when it comes to the Internet.

Good luck.