I misidentified the butterfly in two of the photos in this post; I have edited it to show the correct species name.
It turned out to be a rarer butterfly than I thought; I just heard from the expert who checks my reporting on species that the one in the second and third photo is actually a brown argus (Aricia agestis), bruin blauwtje in Dutch, and not a female silver-studded blue.
This one:
Sorry about that.
Note to GF: Yes, we found another rare one! Rarish, anyway.