Emporium8610

I am planning to start up as a sole trader and intend to use cash-basis accounting. I will be taking payments using an online payment provider that will charge a percentage of the costs of the transaction as a handling/processing fee. Would this handling/processing fee be considered a bank charge and therefore fall under the £500 maximum that can be claimed towards interest and bank charges? The wording on the website seems to suggest that this maximum applies to charges that I incur through the use of my bank's services as a business (e.g. by using an overdraft), so I would like to confirm how these should be treated. Thank you very much in advance.