I was one of the guys who did that drive. It cost Â£20 for electricity and would have been Â£200 in an ICE.
I'm getting a Vauxhall Ampera (european Volt). For me the car will pay for itself in its lifetime. Â£40,000 of fuel savings for commuting alone. See https://twitter.com/#!/dpeilow/status/158629331885752321/photo/1
for the details.