I believe that the 'usual' cut-off time for 'cold calling' as such is 9pm. I was out the other afternoon and it got dark about 4pm, and I felt a little uncomfortable knocking on doors after 5, even then. But whilst I am not suggesting that anybody calls up til 9,. Obviously the whole idea is to catch people in who are not in during the day, So is it wrong to knock say up until about 7.? I know there are people who knock later than this when they are collecting, although they will argue that they are expected by the occupier.