Yep, they are metric HP, the adaptor is also metric, as i found out today.
The front brake (Top pipe fitting) is 10 x 1 mm with an ISO Bubble flair while the lower (rear) is 12 mm, hence the adaptor, which is an inverted double flair, from 12mm down to 10 x 1 mm. Unfortunately my brake line flair nuts are 3/8 UNF, about 9.2 mm as opposed to the 10 mm threads in the adaptor.