Thanks for the advice. I'll start the reclaim process by writing a letter to Premium Credit quoting the Consumer Rights Act 2015 Sections 61 to 76. I'll also ask for the 'default notice' to be taken off my credit reference file.

Hi, I have a Home insurance policy with Premium Credit and the monthly premium is £21.12. This year there have been a number of failed direct debits on my account. Not all my fault as some were caused by Bank errors. For each failed direct debit £20.00 has been charged to my account plus a 'default notice'. This action is becoming expensive and has ruined my credit history. After reading the Consumer Rights Act 2015 Sections 61 to 76, I consider the £20 charge to be unfair for the late payment of an amount of £21.12 Is it worth an attempt to reclaim these unfair charges ? Thanks, JustRaider