IanJ,
I face bryopsis attack some mths ago. I threw in rowaphos and then pray. Seem like that product really giving the bryopsis a hard time to survive. Day by day, I can see small clump go missing, followed by bigger clump going to.
You might wanna try a purple tang, mine seem to tear the aglea apart without me wetting my hands. Together with the rowaphos, the floating bryopsis just couldn't archor themself and dies off.... I battle the aglea with dry hand
One more unclassified observation i made. High alk level seem to kill them too ... Start dosing them, its good for your coraline anyway .. kee..kee...