This is an offtopic request I'd like to put to your attention as you seem to be the right audience.
At the Dutch digital rights organization Bits of Freedom[1] a comparison is being made by Christina van Kuijk on how the different secret services compare on a variety of topics. These include authorizations, data retention policies, international collaboration, and oversight.
[1] https://www.bof.nl/home/english-bits-of-freedom/
Currently there is mostly a language barrier hindering this research, mostly for Denmark, Sweden, Portugal, Austria, and France.
To me this seems to be right up our alley, in addition to international efforts of EDRI, and I hope some of you can help provide some information on these issues.
If you want to contribute you can contact me, or Evelyn evelyn.austin@bof.nl from BoF directly.
Kind regards, Nico Rikken (NL)
P.S. If you find this plug inappropriate, of good, please let me know, so I known for future occasions.