They aren't and in fact no other fluid is - Lifeguard6 is the only fluid that is approved by ZF and all the other brands sold by the various manufacturers are just repackaged LG6. Which itself I believe is manufactured by Shell (and sold by them too - under a different name - which is also not approved by ZF). Either way, if this fluid is designed to work with a ZF box, it'd be worth trying it if you're looking at a $7K replacement trans bill anyway.

I haven't made the enquiries myself, but the ebay page says it "Ships to Worldwide" for the Ravenol fluid.

I bought my fluid from a Ford dealer and even when I screwed him on price it still cost $45 per litre. Next time I will be buying a 20L drum from ZF - think it's under $500 for this. This is unless I can get something from Ravenol.