Do I need a new meter?

I'd be carefull about giving EDF any jip, they can always "make the installation safe" buy pulling your mainfuse and asking you to have your installation certified before reinstating power.

And besides, 3PM onwards is the ideal time (for you!) to have your heating on load/ cook the dinner/run the washing machine/fire up the plasma telly/etc etc, not your fault if the leccy boards equipment is giving you cheap rate at the wrong time...

My time switch on my meter has been out for years. It's great. I can do all my washing, drying and other high power useage for a fraction of the price without having to get up in the middle of the night.

You realise if your supplier notices (quite easy as presumably your 'day' rate is not going up when you provide / they take meter readings), and can prove you were aware of it (that's the tricky part for them), then they could take you to court for fraud?