On further reading, it seems apparent that the Ramosa has a hard to impossible time of going to seed. So it's only spread thru cuttings, and why it hasn't seemed to go anywhere.
The ramosa's a tree type, and while they all flower, they apparently only form seed pods for about 5-10% of the flowers.
There's another post,
https://permies.com/t/32351/plants/plan-breed-perennial-brassica
and some of the posters do have a ramosa, you might be able to contact them about seeds.