You need a 3/8''SAE hose, the ones on ebay are 3/8"BSP when I checked last. Google a company called GAMECO, they do a 3m bayonet x 3/8"SAE hose for around $35. I got a mate to pick me up one last week, they are in Preston Victoria, but have offices in other states.
For the guys who used a 3/8" bsp hose, it will do up, but it will be loose, the thread profile is wrong and there is a chance the thread could jump if you over tighten it. It may seem tight but it is not right so be careful. I don't know why they have two flared sizes for gas hoses that are both 3/8". By the way a 3/8" SAE flare will not start on a 3/8" BSP fitting as its a beez d//k to big. Confused!!!
Cheers Geoff