Ensure you submit your Self Assessment Tax Return online to HM Revenue and Customs for the tax year ended 5 April 2018 by the 31 January 2019 to avoid any penalties and interest.
You also need to make your Self Assessment  balancing payment for tax year 2017/18, and make the first payment on account to HM Revenue and Customs for tax year 2018/19 by 31 January 2019.
