Since switching to three phase my consumption has rocketed to 25,000KWH per annum, despite no significant additional load.

We moved to three phase 3.5 years ago an anticipation of electric cars (which we don't have). 

Since then We have been consuming around 25,000KWH pa according to the meter. 

I've had a second meter fitted and it's validated these numbers. 

When I switch all the RCDs off it stops, so clearly it's my side of the RCDs. 

The house is around 10 years old with gas heating and gas cooking. We have low energy light bulbs. 

The overnight consumption seems to show we're using 4+KWH per hour when we're asleep. 

Load balancing was mentioned and I vaguely remember it from my degree but I don't believe that's it. 

Large donation to charity if you can help me work this one out

thanks in advance