[BarryP]

I was out in my Leaf yesterday evening, for first time with the windows wound down, as it was too warm inside the car. I noticed a single 'click' noise when I slowed down (by lifting off the accelerator), and then sometimes again as I accelerate away. It sounded like a loud relay click coming from the front of the car. Is this normal? Or is something up?

In the owners manual for my new LEAF there is a section that mentions that the driver may hear a variety of noises as various parts of the car functions. In my own car I can hear a relay act as I go into over run on a decent, coinciding with the green sector of the power display coming on .
I would suggest that this is what you are hearing. Don't forget that the LEAF is the only car I have owned in which it has been worth playing quiet music! In most other cars you simply cannot hear the normal operating noises made by perfectly serviceable parts over the rumble of the engine, whine of the gearbox and roar of the exhaust.
Not only can I hear the minute noises made by the car I can also hear the birds singing in the hedgerow.