Welcome to RG Nixonian. I know you're from OZ, but by your screen name, are you by chance a fan of Richard Nixon of Watergate infamy?

Anyway, I'd stay away from rep watch sites unless you get the address from our Trusted Dealer (TD) list. That's why they're TDs, because the Adm & Mods here vetted them and deemed reputable and trusted. Also, if any issues should arise, the Mods here will lend a hand to help get it sorted. Some of our TDs websites give very accurate descriptions of the reps and clearly indicate if chronos and other complications are working or faux. However, it is always prudent to ask the TD all questions before making the purchase!

While a rep might be advertised as a moon phase, it could turn out to be a day/night indicator as you found out. While doubtful, this might be due to a TDs misunderstanding from the maker. A good tell for a true moon phase is the sub-dial should have the moon's 29 1/2 day numerical cycle on its outer ring. A better tell, is to ask before buying!

Good luck in your hunt for Longines reps.