I've gone back over a few things in my head and a couple of things stand out. When she was still in the house, I overheard her talking to a friend, one of the things she said was she wanted to drive more (which she never wanted to do and I didn't make her do). So I then after hearing this, I didn't say anything but I forced the issue a couple of times by getting out of the house first and sitting in the passenger seat. Each time I did this, I remember her coming out of the house and pausing for several seconds before getting in the drivers seat. At the first opportunity though, if we had stopped somewhere, she would race back to the car to get in the passenger seat. She would drive when she said she wanted to but when I forced the issue upon her she couldn't get away from it quick enough.
Some things are making more sense the more I learn, should probably have learnt some of this sooner but it is what it is.