Ok, it was a fairly safe bet.
You are also correct that Fiona was the other keeper, with hers in a community tank.
I have 11 in a 140L/100cm tank. I mainly feed them live bloodworms and small pest snails, but they also take frozen foods quite happily. I feed them what seems to be quite a small amount (a pinch with the aquascaping forceps) 2 or 3 times a day. I'd read that little and often was the way to go. If feeding them a cube of frozen I would estimate I give up to half a cube a day, but split over several meals. I think it's always good to supplement with a variety of foods, and I'm lucky that an LFS has quite good range of live foods.
I also keep mine at the cooler end of the range, 23-24C. They seem fine with this.
I got all of mine as juveniles, and there is a roughly equal split of males and females. 2 of the males are much larger than the others, and their chosen territories are at opposite ends of the tank. They are quite dominant, but the group is very good natured, and everyone comes together without trouble at feeding times.
Even when the fish were in the shop, it was possible to spot if there were any males as some already had the line along the belly, but any without the line couldn't be guaranteed female.
I can completely understand why Mrs Matt would struggle not to purchase them immediately. Their cute little faces, and the way they swim, described in one article I read as being that of an inebriated cow in comparison to the grace with which most other fish swim, an the looks of utter wonder on their faces when they are investigating plants and decor...the little buggers will steal your heart as you watch them.