Changes in Accounting Reference Date

Hi, Can someone confirm whether we can do this please? This is regards to several changes to Accounting Reference Date First year 27/6/21 - 26/6/22 (12 months) Second year 27/6/22 - 26/3/22 (9 months) Third year 27/3/22 - 31/3/22 (12 months and 5 days) Not sure if the third year amendment is possible due to decrease in second year?

Hi,
You are unable to file a CT600 for longer than a 12 month period. Further guidance in relation to accounting periods can be found on our website Accounting periods for Corporation Tax.
You can contact us on 0300 200 3410 to check/amend the accounting periods held on our records.  
We can advise you better with a telephone call, or if you prefer you can write to us at:
Corporation Tax Services,
HM Revenue and Customs,
BX9 1AX
advising what the accounting periods should be and including your UTR.
Thank you.