Many thanks Andres for this information. You have encapsulated in a few paragraphs the information that I need. I am after a bike that assists me up a hill and light enough for me to cycle 50 miles or so under my own steam. I am confident I can physically cope with this mileage with no assistance on a flat route. Would 40Nm be adequate to assist me to cycle up a hill like Pendle for example?
It is a bit of a minefield when you first start looking for a Ebike so I am grateful for the information. I thought a Ebike would keep me going for a few more years and enable me to continue to enjoy the Sunday rides.