Turns out our two girly bunnies are boys. That would explain two things. 1. The friendliness. 2. The ultra-violence. Hopefully neutering will sweeten their dispositions.
The manager of the shop who sold us them as certified females has expressed his sorrow by making us a gift of some rabbit food and bedding. We didn't want to cause a stink, but we thought he ought to know.
Castration costs less than spaying- so there's an upside.
They'll keep their names. Shally and Shaz (short for Shalimar and Sharon) are sufficiently gender-neutral.