Badmother interesting. As you know from other post this is what I did to mount the Brompton fitting onto a non Brompton bike.






Though links (youtube) show a bespoke part. Mine is a DIY solution but interestingly its similar in the way it attaches to the head tube. I had not seen that bespoke part before I designed mine. With mine you just need a stock Brompton block which you then modify using three jubilee clips to attach it. Wrapped in black tape to make it look less industrial

Regards

Jerry