Re: I shouldn't place your hopes in the European Courts
Sorry, but the legislation ISNT driven by the EU after all... (Churchill!!)
As far as I can work out, (and I have been asking questions!) the whole current grab for citizens digital data is an FBI push. (when I say I FBI, of course I mean FBI assisted by NSA advisors)
In the mid-nineties the FBI( & NSA) came to Europe because the FBI (& NSA) couldn't get the laws that they wanted for access to digital-data passed in the US Congress. FBI(NSA) were somehow able to persuade the UK Home Office and agencies to push the agenda to the European Union Conseil (Council of Europe) - this is basically the EU Prime Ministers meeting in Brussels.
Some sort of deal was evidently done with the European Commission Department General Justice and Home Affairs and a draft law was agreed and passed by "Consent by TELEX", avoiding at all cost any debate in the national parliaments. (the only person in the UK House of Lords who noticed this new EU law was told that it wasn't important and that he didn't need to study it and so could go back to sleep)
A memorandum of understanding was signed by (who are now) all the 27 governments of the EU, by CHINA, by Russia, by Australia, NZ and who knows who else?. The MOU is still top secret, many of the other ENFOPOL documents (just the file name for 'police co-operation' in the EU) are sensitive - but are available online here or there (statewatch is a great starting point)
We don't actually know who signed this 1990's MOU - but some governments follow it without having officially signed.
Now, EU courts, ECHR (European Commission on Human Rights) and the ECtHR(European Court of Human Rights) are entirely separate from the European Union and its Court of Justice and the Conseil/Council of Europe deliberations. The EU courts still DO have an important watchdog role.
note that the ECHR and the ECtHR were surprisingly set-up by Winston Churchill who was involved in the devising and drafting of the Convention on Human Rights. The current possibly ANTI human-rights grab for data is coming from UK - possibly still from FBI(NSA) pushing on the UK 'open-door' and is supposed to spread to the other EU states' Interior Ministries, which would have the help presumably from 'EC HOME" as it is now called.
I may well be wrong in all the above, I welcome GCHQ actually explaining the IMP/CCDP genesis from their point of view and how they think Sir Winston would view the current developments?