Use the SA355 to appeal against a late submission penalty of your tax return.
Use the SA355 to appeal against a penalty for late submission of your tax return for the current and earlier tax years. The form includes notes on what counts as legitimate grounds for appeal.
SA356 - Self Assessment - penalty for a late partnership return
Use form SA356 to appeal against a penalty for late submission of a partnership tax return for the 2009 to 2010 tax year and earlier tax years.