This where the confusion lies. The 250w rating is actually a maximum continuous rating, this is what the motor can take continuously without overheating. This is the rating that will be stamped on the motor. However all motors can take more (governed by the controller) often 6-700 watts, in short periods, without damage.. This is still legal so long as the motor is rated 250.Having just read the gov.uk website I can see that it states that an EPAC (pedelec) must have a max power of 250W.