Informing HMRC about moved financial year end

We're an LLP who received a letter suggesting we move our financial year end to comply with the changes to reporting income. I did this with Companies House and it was accepted but I note that Companies House say we also must inform HMRC of this change. I am not sure if a letter confirming this will suffice, or if there is an additional form which I either need to fill in now online or when we submit our return. Please can you advise.

Hi

Please write to HMRC at the following address so that the company accounting period can be changed before you file a Return.
Corporation Tax Services
HM Revenue and Customs
BX9 1AX
United Kingdom

Thank you