Hi Jean-Patrick, there's almost no risks. For several months uk customs have changed rules about nuts and seeds (defra updates). You can simply declare nuts or food seeds, rice on packet. They don't need phyto certificate.
Tropaelum aren't in defra as high risk species, so you can ship.
Some brexit rules are stupid, you can't import Vicia seeds for vegetale use but orher Vicia are allowed, however all species host 3 diseases...