A 250W motor usually tops out at around 30 km/h anyway – also the UK has only part implemented the EU laws leaving some confusion over the point at which an e-bike officially gets classed as a small moped.
The 45 km/h e-bikes will attract attention in Blighty, apparently some posh Londoners (the only folk who can afford them here) have been hauled up for riding them without the correct licensing, but 30 km/h shouldn’t attract excessive attention unless you are scattering pedestrians in the middle of the town centre.
I did have a link to a site with all sorts of e-bike parts and controllers (for building your own); I will try and find that again. From what I remember the controllers (which link the to the throttle) aren’t that expensive, its the motor wheel and batteries which make up most of the price of an e-bike..
