I'm guessing John has a solution for you but........ Ive just had an idea for a quick fix........

Basically it involves using jigsaw with a fine blade and circle cuting attachment. If you can get the plate already in 55mm wide and say 500mm long then keep cutting blanks off as required. set the raduis to 9.5" to cut the radiused part and then square it off. quick buzz over a bench grinder wheel and job done. :dance:

P.S. how much do they cost?