https://help.gosimpletax.com/hc/en-gb/articles/115000027424-My-address-is-different-to-that-held-by-HMRC-how-do-I-advise-them-of-the-change-

https://help.gosimpletax.com/hc/en-gb/articles/115000027424-My-address-is-different-to-that-held-by-HMRC-how-do-I-advise-them-of-the-change-

Click on VALIDATE MY RETURN     Select YES on the radio button question; Is your address different to that held by HMRC?       Enter the date on which you changed your address