Closing bank account - tax accountability

Hi,

I was using a business bank account last year for receiving payments from clients for a side business I'm running.

I've recently started a new main job and want to close the side business. What are the implications of closing the business bank account?

My main concern is if I close the account and 2 years HMRC want proof of my banking transactions then I won't be able to provide the information - please advise.

Thanks
P