The first novel is The Wizard Hunters, next is the Ships of Air and the finale book is called 'Gate of the Gods'

I would HIGHLY recommend them. Imagine England and France are one country, getting attacked not by the Germans but by a mysterious enemy from a different dimension and while working on a secret weapon to use against them, Our Heroine and a group of her fellows get shifted into another dimension (also being attached by the same enemy), where she meets with two classic 'barbarian warriors' - only their culture is a more tropical location and the most functional and realistic matriarchal so I've read.