Be careful as the 3/8 and 10mm fitting threads are nearly the same but not the same enough if you see what i mean.
The fitting are cheap so maybe worth buying a couple of imperial ones as well.
Use the kunifer pipe as it bends really nice and easy for fitting purposes, plus of course doesnt rust.
Try a google seems mid 80s was change over, but some are mix and match ie imperial unions and metric hoses!
Lynall