Would be better if they had given us some official id badges.
You could make your own, it would have as much authority as the LOA.
Small shop owners don't care if you've got a letter from the queen, they will not want you doing ANYTHING in their shop and will tell you to leave/chase you out if they even think you are up to something!
I tend to avoid any task that requires
photos inside a cornershop - you'll get rumbled PDQ and asked to leave.
'introduce yourself to the employee' - They don't care.And will view you with suspicion.
Ask lots of detailed questions like "Do you stock brand x vape? Have you got a vape recommendation?" - no-one asks the geezer down the cornershop that.
Tasks I love
Outdoor photography - take your time and no-one bothers you.
betting shop tasks - they are weird places where EVERYONE is on their phone every 30 seconds.
supermarket tasks - Literally no-one cares!