To the extent that Ven. Ñanavira's ideas have been brought up, here are exerpts from a couple of his letters that might help in understanding his take on epistemology and whether or not things exist apart from us.
Of course, since knowledge is very commonly (Heidegger adds 'and superficially') defined in terms of 'a relation between subject and object', the question of the subject cannot simply be brushed aside -- no smoke without fire -- and we have to see (at least briefly) why it is so defined. Both Heidegger and Sartre follow Kant in saying that, properly speaking, there is no knowledge other than intuitive; and I agree. But what is intuition? From a puthujjana's point of view, it can be described as immediate contact between subject and object, between 'self' and the 'world' (for how this comes about, I must refer you to PHASSA). This, however, is not yet knowledge, for which a reflexive reduplication is needed; but when there is this reflexive reduplication we then have intuitive knowledge, which is (still for the puthujjana) immediate contact between knowing subject and known object. With the arahat, however, all question of subjectivity has subsided, and we are left simply with (the presence of) the known thing. (It is present, but no longer present 'to somebody'.) So much for judgement in general.
The ordinary person (the puthujjana or 'commoner') thinks, 'I feel; I perceive; I determine; I cognize', and he takes this 'I' to refer to some kind of timeless and changeless ego or 'self'. But the arahat has completely got rid of the ego-illusion (the conceit or concept 'I am'), and, when he reflects, thinks quite simply, 'Feeling feels; perception perceives; determinations determine; consciousness cognizes'. Perhaps this may help you to see how it is that when desire (craving) ceases altogether 'the various things just stand there in the world'. Obviously they cannot 'just stand there in the world' unless they are felt, perceived, determined and cognized (Berkeley's esse est percipi is, in principle, quite correct); but for the living arahat the question 'Who feels, perceives, determines, cognizes, the various things?' no longer arises -- the various things are felt by feeling, perceived by perception, determined by determinations, and cognized by consciousness; in other words, they are 'there in the world' autonomously (actually they always were, but the puthujjana does not see this since he takes himself for granted). With the breaking up of the arahat's body (his death) all this ceases. (For other people, of course, these things continue unless and until they in their turn, having become arahats, arrive at the end of their final existence.)
Ven. Ñanavira described his approach to the Dhamma as "vertical" as opposed to "horizontal" or linear, i.e. it is based on immediacy and its relation to reflection. And since the immediate world is given (granted from a particular point of view, i.e. as "shaped" in a particular way) before reflexion, it stands autonomously whether we reflect upon it or not. To hold to a linear epistemology without recognizing its derivitive nature distorts how we actually experience the world (it lends itself to a belief in an outside world apart from our senses, failing to recognize that phassa occurs at the immediate level).