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Thank you all for your answers, which were very helpful. It's sorted out, but took several days, and three trips to our local branch!!
After telling us on the phone our overdraft had been completely cancelled, we then got a letter saying we'd got the full overdraft for another year!! Then a few days later we got another letter saying our request for an overdraft had been turned down, and our overdraft cancelled. My Husband went back into the branch, where they told him that the first letter had been sent in error, but as it was their mistake, they had to honour it, and therefore we do have the overdraft for another year. Don't you just love banks??!!