Most people on economy 7 use 40% of their electricity during the low peak hours - they set their immersion heaters, tumble driers, storage heaters, dishwashers etc to come on at night.
If you are the same, you have being too much due to them not maintaining their meters properly. You are not an electrician, it is not 'your' meter and you do not have the authority to tamper with it in any way,
I would strongly argue for a REBATE - you have been paying too much for night time electricity when you have had your most power hungry electricals on.