I'm working at a house and the previous sparky has been a bit of a cowboy - end of cable left in gaffer tape, non MF free junction box to be hidden above new ceiling, spur off of a spur, choc blocks everywhere. Would you say anything or just get on with your work and leave? I don't think they seem terribly safety conscious as the husband had drilled through a cable in the wall and just asked the decorator to carefully fill it (I was there).