I was there 6 years and the trouser issue was always being brought up, and as you know No Trousers, so EmmaB your spot on there.
I know someone who complained bitterly about it, raised it as a grievance with HR etc, but was told the company had done market research with passengers and apparently they associate trolly dollies in trousers with low cost airlines and skirts with full service companies. And they said because Flybe stands for 'low fare, but not low cost' there will never be a trouser option for the ladies
.