Changes to Council Directive of 6 February 1970 on the approximation of the laws of the Member States relating to the type-approval of motor vehicles and their trailers (70/156/EEC)
EU Directive 1970/156
Made by Commission Directive 2004/78/C of 29 April 2004 amending Directive 2001/56/EC of the European Parliament and of the Council relating to heating systems for motor vehicles and their trailers and Council Directive 70/156/EEC for the purposes of adapting to technical progress
From legislation.gov.uk's record of changes, the official one: see it there.