The other thing that came to my mind is that London (New Bond Street) experience was very poor. I had to wait for 1 hr for the SA (though I had an appointment) and then there was another person after me so no champagne (not that it's necessary but it was my first big bag), quick check and next person.
I had a proper experience in a small boutique in Warsaw but they typically have few visitors so my friend and I spent 2 hours there, drinking loads of champagne, chatting with SAs and SM and trying other things.
I guess it's not that important for some but if by 'boutique experience' one means the exciting and celebratory time, one might be disappointed.