Yes, I am a swingy or floating voter. To be a staunch supporter of a particular party means a party can behave how it likes and rely on their faithful voters regardless. It has no need to do any persuading because no matter what the party does, they will be assured of those votes.
Floating voters like me tend to listen to all sides of the debates/arguments at the time and then vote accordingly. Hence we get a change of party from time to time. Labour obviously didn't cut it last time but in the future, who knows?