 In 2016 a Bach CD was released (also on Aeolus), using an original transverse flute from Bach's times.From 1984 to 1988 Holtslag taught at the Guildhall School of Music in London and was a lecturer at the City University, London.In 1988 he was appointed a professor both at the Royal Academy of Music in London and the Hochschule für Musik und Theater Hamburg.