Joseph in Czech makes them, his quality is impeccable.
His daughters Anna email is
anna.cingrosova@seznam.cz
You need to deal with Anna as Joseph’s English is limited.
I have many parts from Joseph for other BSA’S and all have fit perfectly
I Second Darren C's message. I just bought one from Joseph (through Anna). Took 3 months to get to Australia, but is a brilliant reproduction. Looks immaculate. Wouldn't hesitate to recommend.