UK Chartered Accountant to Provide Certificate of Confirmation

I need a Chartered Accountant based in the UK, who is an accredited member of the ACCA or ICAEW, to provide a signed, headed letter confirming that my accounts for the last tax year (2017-18) were correct. I am the sponsor for my husband's visa and as such, I need an accountant to confirm that the amount submitted to HMRC was correct as based upon last year's accounts (the tax return has already been submitted - I do not need you to file my taxes, simply confirm the numbers).
This is a very quick, straightforward job, as I'm a sole-trader who files on a cash basis. I can provide an example of the letter my last accountant used for the same purposes a couple of years ago if needed.