I am trying to recall... The mount for the hook has a stiffening lip that forces you to orient the mount forward, as that lip interferes otherwise with the bridge to the rear triangle. However, for that orientation the mount interferes with the rear triangle after it gets flipped in the fold. In my case there are more factors, as I try to squeeze in more chainrings, but the above is there for any Brompton, I think.
I think I know what you mean now (Turkish green is my bike), I might shorten the arm so it can be located similar to the black one. Will give that a try if all else fails.
