Hi Rosie, it looks like hive beetle larvae. I think I can make out the 3 sets of legs at the front on one of them. Have you inspected that frame as well as the frames adjacent to it, to see if anything is going on in them.
My suggestion is to always inspect Flow frames before harvest just to make sure that everything is fine with them. There could be brood in the frames, that got slimed during your previous harvest, or some bees could have gotten trapped before slimed. There are a few possibilities, so that’s why I make that suggestion. You’re the second person in S.E. Qld.with a similar outcome within the past week.
cheers