I am going to apply as self-employee, the nature of my business is a combination of Cash, Payslips and cheques, so Its hard to show the whole amount of earning with bank statement but I have a certified accoutant who is going to give me a confirmation letter about my earning and I am going to send my business account which shows profic and loss and the balance.
I just want to know business account and accountant confirmation letter are different sources or not ?

I am already registered as a self employee and I have employes liability insurance.
Tnx