Bit the bullet and bought the Borough waterproof backpack in copper. Thought people might find it helpful to see the size compared to the bike. : r/Brompton
Brompton Borough Waterproof Backpack - Graphite
MOCHILA BROMPTON BOROUGH WATERPROOF BACKPACK
Brompton Borough Waterproof Backpack - Graphite
BROMPTON Borough Waterproof Backpack M in Graphite | 808 Cycles