If you want a chordless mower for a small lawn, I would reccommend a battery powered mower. These have in the past been badly under powered and the running time has been far to short.
Bosch have recently brought out two new Rotak mowers which use Lithium ion batteries that are excellent.
I would strongly reccommend these two mowers, they would make much lighter work than a hand powered mower and they can comfortably deal with twigs and uneven ground.
I found a great website, www.turfshop.co.uk, that has some great deals on mowers including the two Li-ion battery powered mowers.