the ICAO english level certificate is not part of the requirements
From the nice people in EASA
Air traffic controllers and student air traffic controllers shall not exercise the privileges of their licences unless they have a valid language proficiency endorsement in English and, if applicable, in the language(s) imposed by the Member State for reasons of safety at the ATC unit as published
in the Aeronautical Information Publications. The language proficiency endorsement shall indicate the language(s), the level(s) of proficiency and the expiry date(s).