I want my money back too - from Thames Water!

It has always been my understanding that utility companies are not allowed to hold customers excess payments made via Direct Debit but I might be wrong. Either way, I don't know what the balance limit is but I am confident some other GNetters will correct me on this.

In your position I would certainly complain to the water company and also raise this matter with your local MP.

I will watch this thread with interest though.

Keeping my fingers crossed for a positive outcome Alie.

If you havent already tried it, I suggest simply asking them to refund that excess immediately rather than offsetting it against next year's bills. Preferably by email rather than phone, so that there is a record of your asking and of their response, which can be useful if you need to take the matter further.

Regarding the meter though - as it has to be read manually, I presume that it isn't a smart meter? I would ask Thames Water if they can remedy that right away, so that future bills are not based on wild estimates.