To my knowledge and I suspect many others Mort ,the black terrier has only ever used another black terrier for an outcross .No lads I know would dream of going to another breed to fix anything .If we are to believe the gene pool of blacks came from a few yards way back then there’s no tighter breed than a pat .
You poodle enthusiasts seem to have an outcross every other breeding ,each one the holy grail to fix the breed .
Yours are so f****d up it’s about time you created a new name ,how about Mortlingtons .