When we were looking into it about 3yr ago in GB, the vauxhall corsa 1l were cheapest to insure and Quentins were the cheapest insurance by a mile.... girls were cheaper to insure because of the lower risk factor but thats been legislated against as 'discriminatory'. Parkers site lists the current insurance groups- they do change depending on the dynamic of the buyers so the corsa may well have gone up a bracket or 2 as all the young 'uns pounced on them!
The new insurance grouping is explained at Parkers
here and you can use the selector
here to find group 1 (the cheapest) cars. Watch the different models with older cars as they can bump up a premium if they're rarer/ more upmarket models which are harder to source the usual damage suspects (eg colour coded/ painted and different shaped bumpers, light units)
It might be worth checking AAs black box scheme for a long term insurance reduction if she's a careful lass, I have no idea if it'll be reasonably priced though! Good luck to you both!!