Complex sentence: At the time he insisted the single was a one-off, and that he was purely a producer and not a rapper/singer in his own right, however has since released his own solo album, In My Mind.
Split into simpler sentences: At the time he insisted the single was a one-off, and that he was purely a producer and not a rapper/singer in his own right. However, he has since released his own solo album, In My Mind.