My solution for carrying water: The SKS bottle cage adapter goes on/off the bike in seconds, and can be attached to the steerer tube or seatpost. Simple and inexpensive. : r/Brompton
Cycling essentials] Brompton specific bottle cage mount adapter, 2 seconds quick release! The predecessor B-Mount system.
The Brompton bottle cage dilemma - does the Monkii have the answer? - YouTube
Cycling essentials] Brompton specific bottle cage mount adapter, 2 seconds quick release! The predecessor B-Mount system.
Monkii Cage with water bottle on front stem of Brompton | MELBOURNE BROMPTON CLUB
BROMPTON WATER BOTTLE CAGE ADAPTER ON STEM HEAD TUBE (TRIGO)
A neat solution – water bottle holder for Brompton – Kite*Surf*Bike*Rambling
Waterproof Stem / Saddle Water Bottle Bag for Brompton
monkii Clip B + monkii V Cage - Brompton Water Bottle Cage System | eBay
My Orange Brompton: Brompton Water Bottle Solution
Holding Water Bottles on a Brompton | Adventures on Brompton