Brompton claims is not about patent but about design.

Brompton claims that the Brompton bike has a unique design not mandatory to make a folding bike (i.e. that the design of the Brompton doesn't come from industrial requirements but is a kind of piece of art) and that Chedech (and we can expect also other clones) copy the unique design of the Brompton bike.

Copying the unique Brompton is like copying a Picasso, Rembrandt, unique design furniture... a kind of copyrights infringement.