I've got 3 petrol lawnmowers, they're all a pain in the **** so I went down to toolstation and bought a 40V battery one, It's wife friendly, comes with 2 batteries and a charger for £199, one battery does both of my normal sized lawns.
I've got 2 dogs so a bowling green lawn isn't my priority but I'm impressed with it, cut isn't the widest but more exercise at my age isn't a bad thing
http://www.toolstation.com/shop/p36634?table=no
The same lawnmower with one battery is the same price which is a bit odd as they're £80 each