My setup on Brompton is SON Delix hub I bought as built wheel, SON Edelux II and SON rear light. Total cost was very higher, but I went for the most reliable option which also provides probably best in class optics (Edelux II reflector is designed by B+M), bullet proof construction of everything and least resistance when lights are off. According to my research it’s the best you can get for Brompton.

The interesting thing about Birdy is that R&M paired hub/lights themselves, so we can be sure lights will work with best performance. Another thing to consider is location of light. I’m not sure if Edelux II will fit seamlessly and installing B+M light only to have it fail after a year is something my heart will not take. If Supernova light would’ve had light sensor and automatic switch it would be even better.

Even if the SON hub would’ve still available I’m not sure if it’s logical investment considering that bike already comes with hub, front/rear lights. Still, I wouldn’t definitely recommend SON hub and lights as in my opinion they have best performance and quality in the industry. Worthwhile investment assuming you’d like to pay once.