TIBROMTACK Titanium Gooseneck Seat Post for Brompton Bicycle Saddle 31.8mm Folding bike New Type Rod 550/580mm Gr9 Ti Accessories (GOLD COLOR, 550) : Amazon.co.uk: Sports & Outdoors
Brompton saddle | black saddle wider width
Restrap City Saddle Bag – Condor Cycles
Marvin Saddle Bag and Quick-release Mount Kit for Brompton
Another quick review: Ergon ST Core Prime saddle (and GP3 grips, too) : r/ Brompton