tachograph:
There are occasions when you can have reduced weekly rest periods on 2 consecutive weekends but it can usually only be done once between 90 hour rest periods (this will usually be a holiday).
This is incorrect.
If I take a 45 hour rest at the start of week 1, and a 45 hour rest at the end of week 3, then I can take a reduced rest at the end of week 1 and the beginning of week 3 (or in other words, at both ends of week 2). All that is required is to compensate for the reduced rest before the end of the third following week.
I used to do this regularly when I was running my own truck, and it never once flagged up as an infringement on my tachograph analysis.