Fauxmo is here it lets one raspberry pi act like many devices so alexa can turn them on or off, I got this working with my sockets in the lounge yesterday. Unfortunately I started setting this up when the christmas tree was up, and it is obviously down now, so I can say "alexa turn the christmas tree on" and that socket comes on, but there's nothing plugged in there now. Not sure it works with the dimmers, doesn't seem to at the moment though there's no good reason for that. Still, progress, alexa possibly being some use around the house after all.