CIB officers were now investigating and were checking any CCTV footage that might be available.
The offender is thought to be a Maori or Pacific Island man, about six feet tall and of solid build. He was wearing a bucket hat and a maroon hoodie.
In last September's incident near the same shops, Ms Knight, a mother of six, was punched in the head when she intervened as a young man tried to snatch an older woman's handbag.
Ms Knight suffered a fractured skull, a brain bleed and needed surgery.
Her attacker, 17-year-old Hendrix Hauwai, was jailed for four years and nine months.
Anyone with information about today's attack can contact North Shore CIB on 09 477 5261.