Commission Implementing Decision (EU) 2018/2023 of 17 December 2018 on amending Implementing Decision (EU) 2017/1984 determining, pursuant to Regulation (EU) No 517/2014 of the European Parliament and of the Council on fluorinated greenhouse gases, reference values as regards reference values for the period from 30 March 2019 to 31 December 2020 for producers or importers established within the United Kingdom, which have lawfully placed on the market hydrofluorocarbons from 1 January 2015, as reported under that Regulation (notified under document C(2018) 8801)