Nice to hear from someone which drives a BX in Australia.
Just to to be shure: you're looking for these:
[quote]Tony45 (./2) :
BX 16 Soupapes
....
[quote]
If it is so: they are called 'monogramme' in french (this may also help you in addition to find some)
Don't hesitate if you're looking for other parts as well.
Cheerio,
Stefan