The Easi-fit uses a throttle, which I was given to understand was outlawed in 2016, or thereabouts? Only pedal assist, not pure electric power, is permitted on bikes or installarions after that date.
Edit - yes, from January 1 2016, the only throttles legal within the UK's EAPC legislation are those that assist the rider without pedalling up to a maximum speed of 6 km/h (3.7 mph) – i.e. starting assistance only. ... If the cyclist pedals at the same time then the throttle can still assist up to the general limit of 15.5mph. The Easi-fit website describes being able to ride using only the throttle, which would result in a good pistol whipping from the feds, and rubber hose across the soles of the feed from the courts.
Edit edit - the witeless thumb throttle is optional, so ignore everything ive just said, and simply don't order it.