Thanks ProDave (that sign post is the only accurate bit of information I've ever seen come out of Scotland)
The problem I have is at 0100 do my 3 storage heaters & immersion heater go on full rate for an hour.
Doc Hudson, It's a modern meter operated by a radio signal & the changeover between tariffs is spot on time wise.
Thanks Evans Electric, I have plug in timers in use, It's just the first house where I have been all electric so I'm still getting used to it.