I disagree with this answer.
He's discussing a different level of cognition. In the first sentence, he admits that contact is defined in terms of the three-fold coming together. But he is discussing a basic assumption underlying the default subjective experience of that contact — i.e. that there is a subject coming into contact with an object. The essay is convincing the reader to abandon the senses of : identification with that subject, and objectification of the object.
While SN 12.44 is stated in terms of Dependent Origination, it's not about the experience of Dependent Origination! It's about how the experience of the world arises. In our experience of the world, visual forms arise via three-fold contact with the eye. That model is key to our conventional experience of the world. But DN 15 (mentioned in Ven. Nanavira's footnote [a]) is about how contact per se arises from name-and-form, independent of any concrete world model, which is why it uses the much more abstract terms of resistance-contact and designation-contact. As he says in footnote [a], resistance-contact isn't five-senses contact (his "cakkhusamphassa &c."). In terms of our direct experience, cognition in terms of forms arising via three-fold contact at the eye is nama — not rupa in its own right — though it concerns rupa. It's a useful model which Ven. Nanavira does not wish to spurn, but Ven. Nanavira contends that to carry the Buddha's program to completion, we must release attachment to any implicit subject/object duality in the background of cognitions which are in terms of that model.
in contrast to what nanavira is stating here, for the buddha, contact arising from the meeting of sense object, sense base, and sense consciousness, is essential for sentient experience whether one is enlightened or not.
He does not deny that! Contact occurs in the arahat. He's just saying that that's not the key issue for purposes of phassanirodha. See footnote [d]:
Phusanti phassā upadhim paticca
Nirūpadhim kena phuseyyum phassā
Contacts contact dependent on ground—
How should contacts contact a groundless one? Udāna ii,4 <Ud.12>
It must, of course, be remembered that phassanirodha in the arahat does not mean that experience as such (pañcakkhandhā) is at an end. But, also, there is no experience without phassa. In other words, to the extent that we can still speak of an eye, of forms, and of eye-consciousness (seeing)—e.g. Samvijjati kho āvuso Bhagavato cakkhu, passati Bhagavā cakkhunā rūpam, chandarāgo Bhagavato n'atthi, suvimuttacitto Bhagavā ('The Auspicious One, friend, possesses an eye; the Auspicious One sees visible forms with the eye; desire-&-lust for the Auspicious One there is not; the Auspicious One is wholly freed in heart (citta)' (Cf. ATTĀ [c].)) (Salāyatana Samy. xviii,5 <S.iv,164>)—to that extent we can still speak of phassa. But it must no longer be regarded as contact with me (or with him, or with somebody). There is, and there is not, contact in the case of the arahat, just as there is, and there is not, consciousness. See CETANĀ [f].
In summary, the key issue for purposes of phassanirodha is the abandonment of the subject/object duality — "I am making contact/contact is made with me". This is how I construed his footnote — "But [contact] must no longer be regarded as contact with me (or with him, or with somebody)."
what the buddha very differently and very specifically refers to as instants of sense consciousness that arise and fall away moment to moment.
Can you point me to the sutta you're thinking of?