Mains powered, 7-day electronic timer (North Road)
Complete with instructions. Bit fiddly to set up but seems to work. Internal battery doesn't last long if unplugged but, so long as it's plugged in and mains is on, seems to be OK. Can sets several Off/On cycles during a 24 hour period and can be different for each day of the week.
This offer has been gifted to someone and is no longer available.