Phew....where to start.
1. Get those storage heaters checked. I know of people who had old heaters which were inefficient and costing an awful lot of money, at the same time, check the wiring, they could be connected to day time energy & not Economy 7????
2. Monitor your useage, switch everything off and then check the meter, is there anything else running? Then start switching things back on individually and see what item is making the dial whizz round quickest!!
3. Immersion heaters? well i switched mine on (eco 7) 3 years ago and havent turned if off since! Basically when u switch it on during the evening u r paying higher rate due t Eco 7 and its having to heat up a full tank of cold water from scratch?
4. Are you using Eco 7 effectively. I put my washing machine/tumble dryer/dishwasher on at night to take advantage of the low rate.
5. Get on line...plenty of web sites offering to compare your supplier with others. Try www.buy.co.uk or www.thisismoney.co.uk
6. Hassle your supplier, most of them offer advice and energy saving tips. Keep pushing them to get someone out to your home and let them tell you where you are going wrong.
Good Luck