OK, so I did some piriformis stretch, then some lowerback stretch, then some hamstring stretch, did 20 + 20 bodyweight squats, then 24 kg KB deadlifts/squats 10+10, then gone with one-leg straight leg deadlift with the KB (kettlebell), then did 4 sets of 10 swings with it, back to 1-leg deads, then did the stretches again...
Now mobility is basically 100% and pain is almost none (a very faint pain sensation when I get past the knees in a hamstring stretch) but that's pretty much it. Will see what happens next.