Five-year-olds are an unpredictable bunch. We were hurtling across Venice lagoon in a water taxi when suddenly the engine cut out with a loud bang. While I was scanning all directions trying to decide which offered the best chance of not drowning, my particular five-year-old was giggling and loving every second. The engine re-started, we shot off again, and I slouched back content that the next eight days crossing northern Italy were going to be absolutely fine. Now, I know Venice, Florence, Pisa and Bologna aren’t the first places that come to mind when you think of being adventurous, or goin…