Morgan discs have always been Morgan specific traditionally although EBC list standard and turbo groove versions in their catalogue.
I have Mulfab grooved discs on my plus 8 with standard calipers and the brakes are excellent.

1969 4/4
1995 plus 8
1996 Plus 4 4seater
2002 Aero S1
2013 M3W
2014 Plus 8