Accounting Letter (income certificate)

I am looking for an accountant or accountancy firm in the UK who is a member of a recognised supervisory body (ICAEW, ICAS, ACCA, CIPFA, IFA, CIMA) to certify my personal income for the last 12 months from date to date. It's a very straightforward letter and I have a draft with all information ready to verify and sign (see a template in attachment). I will provide all information you need to verify the letter - invoices, bank statements, payslips, dividend vouchers, minutes and all other relevant documents.