Hi @LawRam, I doubt it’s worth having someone out to check your meter yet until you’ve performed a few more sanity checks yourself.
I’m unsure as to the exact figure but if no fault is found, you would be struck with a bill probably £100 or so:
3.6. If you ask us to test the accuracy of your meter, you must pay us an amount to cover the cost of the work being carried out. We’ll tell you what this amount is at the time, and we’ll provide a breakdown of the costs if you ask us for one. If the National Measurement Office decides that the meter is operating outside of the statutory limits, we’ll refund the payment to you.
I believe the standard procedure is to install a secondary calibrated meter before your meter, and as standard meter replacements are normally around £100 so that's probably a good ballpark figure for the costs that might be involved.
Is the radiator connected into a standard socket (in which case it’ll almost certainly be 3KW) or hardwired into the wall (where it could be a higher power)?
Call it 18 days, 405kWh. Say you run a 3kW heater in the living room on average for 4 hours a day (not unreasonable with the cold weather we’ve had), that would be 216kW of your 405kW.
That’d make your monthly usage about 250-300kWh excluding your heating which is not unreasonable. Mine last month was over 300kWh and I have gas central heating.
Set top boxes (especially old ones; have you ever felt how hot they get?), large TVs, older appliances, and electric cooking appliances could all also be culprits for higher than expected usage.
You might want to consider something like a plug in power meter (example) to use to test the consumption of various appliances in your house.
Or alternatively, if your meter is accessible in the flat, maybe something to monitor the whole house consumption yourself (example).