Ha, try Kips Imorts in Texas. If no luck there, the Roadster Club in England sales all kind of parts and the exchange rate is not bad at all.
Shipping is competitive. I think you have to be a member to order parts, but if you are just starting, they will be your go to site.
Of course there are a few around and most are always willing to help.
Great Forum here, many helpful members.
View attachment 61619View attachment 61620View attachment 61621View attachment 61622Malbaby, so what am I, Chopped Liver. LOL
Just try to keep cool, understand it's been a bit warm down under.
You should be able to find a suitable M/C replacement, even it it not completely original, depending on the mounting method.
Being mounted under the floor, a non original M/C could be used....eg Ford or Mercury 1949-51....easily obtainable...or even a combination booster/master cylinder [hot rod style]
Also consider mounting a remount booster under the floor also.
IMHO...good brakes are more important than winning a concours.