If you was going to part with your hard earned beer tokens, it would be worth checking the thing does indeed conform to the reg's.
"Electric-assist cycles & UK law
In the UK, riders must be at least 14 years of age.
Electric cycles are classed as pedal cycles provided they conform to the pedelec definition (motor power output inversely related to speed, and power cut whenever the rider stops pedalling) and have a powered-assisted maximum speed no greater than 25kph (16mph, but you can pedal faster unassisted). They must also have average power output limited to 200W (250W for an electric tricycle or tandem) and weight limited to 40kg (60kg for a tricycle or tandem).
The Department for Transport produces two relevant factsheets about electric cycles and the law: Electrically Assisted Pedal Cycle (EAPCs) in Great Britain and Regulations For Powered Two And Three Wheeled Vehicles .
The "pedelec definition" is one area I'd need to be happy with ;
"Since June 2003, only the pedelec type of electric bike benefits from being classified as a pedal cycle; throttle-controlled electric bikes (e-bikes) are now considered mopeds1. With pedelecs, the amount of assistance you get from the motor reduces as go faster, and cuts out altogether once you reach 25kph. The motor also cuts out if you stop pedalling. This ensures an intuitive bicycle-like ride
..and also it's weight.
Buying one and then finding it doesn't conform to recent regs would be upsetting !
Not sure I fancy one of those though, it doesn't look as good as a c5 and I doubt it's performance is all that great.