Thank you. Not sure I like the system with the plastic fittings under the bag

https://www.ortlieb.com/wp-content/t...rc_detail8.jpg

I have been thinking of using this system for several folders. It is possible to buy several different bags or baskets to atatch on the rear rack and you can atatch an adapter to stuff you already own to click it on. You can also hang side panniers from the thingy I linked to together with the rack top bag. Not so useful with the Brompton but could be used with other bikes.

Rixen & Kaul, KLICKfix Adaptersysteme Fahrradzubehör, Solingen, Taschen, Körbe, Werkzeug

I never leave the B out of sight so I am thinking of maybe removing the lock and grinding down the red button for the B.