Yes, and there are other times when mistresses get them mixed up too. There's that time when a prefect (the 'steaming nit' Gina something?) mistakes them and tells Lawrie Miss Keith wants to see her, and Lawrie comes back all cross because she went and tidied up and almost put on a clean blouse.

I think those are all very understandable. I suppose I was just interested in who did or didn't mix them up making their peers. I know it would have been dull to have every conversation outside their social circle behind with a who's who check, but I could imagine diffident Esther when new hovering when she sees a solo twin to check it's Nicola, not Lawrie...