Reg.23 of the Public Contracts Regulations 2015 (PCR2015) is probably one of the shortest and most straightforward ones, as it merely replicates Article 23 of Directive 2014/24 and indicates that any references to nomenclatures in the context of public procurement shall be made using the CPV, which is in turn defined in reg.2 PCR2015 as the Common Procurement Vocabulary as adopted by Regulation (EC) No 2195/2002 of the European Parliament and of the Council as amended from time to time. Nothing to add (on my part; Pedro did find some things to say).