Yes. You should be able to amend it on ROS. Basically follow the same steps as if you were filing an original return. There are a few boxes to tick on the first page of the return and you'll obviously need to enter the dividend income and rerun the self-assessment procedure but if you miss anything the program will highlight the omitted items so it's hard to go wrong.Yes I did do the Income Tax return on ROS already, so I guess it’s a matter then of just updating/amending that?