Having tried for some 4 years to get a BP du Sud account closed and the balance transferred to our Credit Agricole account I decided to write to the Mediateur for the BP.
Almost immediately BP closed the account and transferred the money.
I assumed this was the end of things but yesterday I had an email from the Mediateur agreeing that BP du Sud had been unreasonable and that I deserved not only a proper explanation for the delay but also 300€ compensation.