Vellalas are not all Nayars

http://shodhganga.inflibnet.ac.in/bitstream/10603/9570/35/10_chapter%202.pdf
Basically whether the Nayar is a caste, a community or caste had
been so far regarded as vogue by scholars. The doubt regarding the
constituent of Nayar people was exposed by Joan P Mencher (1969). KS.
Singh (2002) introduced various categories of Kerala people which did not
put Nayar as a general category. Velalla community migrating from Tamil
Nadu to Kerala has been also considered to be Nayar. They had been
described as paddy-farming clans who had been expert in irrigations. Some
authors observed that the Nayar represented intermediary community between
the Brahmin and the non-Brahmin society which characteristically practice
matrilineal descent rule (Rajeevan 1995). They had been in general
indigenous landowners and rulers. Widely accepted social category under the
Nayar represents traditional professional group. Kiriathil Nayar, Sudra
Nayar, Charna Nayar, Athikurussi Nayar, Velakkatala (barber), Velutedat
Nayar (washerman). Under the Charna Nayar there are Akath Nayar (the
accountant, generally distinguished by the title Menon), and Rurath Charna
Vellalas are not allNayars
Dr.Kanam