Instead of an hourly rate some people charge by point, maybe £60 a point, if you do that and say you wire 6 downlights in a room with a 1 gang switch, would you charge for 6 or 7 points, similarly if you wired a spur controlling a single socket is that 1 or 2 points. Maybe even go as far as charging a switch out at £60 per switch so a 4 gang switch would cost £240 to install as opposed to £60 (or nothing if you include it with the installed lighting). What's the consensus on that one.