The five-piece - Harding, Cheryl Cole, Nadine Coyle, Kimberley Walsh and Nicola Roberts - ended their hiatus in October (12) by announcing plans for a new single, album and 2013 tour.
They are gearing up for their shows, which are set to begin in Newcastle, north-east England on 21 February (13), and Harding reveals the bandmates are getting along a lot better than they have in the past.
She tells Britain's Sunday People newspaper, "It's great being back with the girls, we're not quite as fiery as we used to be and we are far more grown up about making decisions about the nitty gritty of our tour.
"We're a lot more honest and hands on this time and have much more of a say. There aren't any rows or disagreements... any more as we're all in or approaching our 30s.
"We've found there are ways of compromising and meeting in the middle... We just want to get the best out of ourselves and achieve the best we can do for the reunion.
"When we were in our 20s we lived and breathed each other and we were together all day, every day apart from holidays. You feel suffocated sometimes when you do your job so it was nice to have a break."