She is larger than he is by ~1cm in length and ~0.5cm width. Yeah they could be different instars. They were the same size when I got them about 4 weeks ago. The female moulted earlier this week, the male has not moulted yet with me. The second unmoulted female is still the same size as the male.
I asked the seller how many moults remained, he said he wasn't sure, but that he thought the male had 2 left and the females 1. If this was the case then the female should have been adult at the last moult so clearly there is a mix up somewhere along the line. Maybe the females had 2 left and the male only 1? The info I have on them suggests 9 moults for a female and 8 moults for a male, does this sound right?