|>>|| No. 6196
>Turns out it was rectifying past underestimation
Sounds about right from your description, particularly in the new estimated reading is close to the current actual. From now on, give them an actual reading about a week before they produce your bill, then at the same time every month. Relying on estimates generally isn't in your interest, since if they overestimate you pay too much, and if they underestimate you'll get a shock. You might also have a problem if they overestimate by too much, where they'll bill you for something like £10k because they think the meter has rolled around.