Brompton owners

I just need someone to tell me what brompton bag to buy

I've got 3 different versions, the "touring" one (old version from 10 years ago), a cute small black canvas one with leather straps, and the mega basic open shopping basket one... Recently that's the one I've been using the most, I just throw whatever bag (ortlieb saddle bag, backpack, etc used the rest of the week when using a full size bike) in it and boom! Flexible capacity if shopping because opened, I add my good old cotton waxed poncho on rainy day... Completely faff free, and the cheaper option, even if not the most desirable, trend-wise...