Low flow devices are going to be an interesting problem for agents and those who self manage.
You will now need to check that the devices are still present upon vacating as for many people, they will arrange to remove them.
Not such a biggie really...1 minute measure under each device tap and 9ltrs or less no worries. Not a big job when doing a tenant changeover really....not for me anyway. Looks like they are an easy fit....change washers while you're in there and no complaints about leaks either...!
Think positive...