At a "no runways" aerodrome, I should guess there are no numbers to land on, either...
So I would land on the most likely spot - if really determined to trust such an unlikely place... Then again, if there still were a landing T in these times, I'd be happy to take guidance from it... As I understand things, my little queer BE country is one of the last to still impose them. As uncouth as the country may be, though, it hasn't had "no runways" fields for the last fifty years or so. I did still have to study them though, and their rules, for my "air law" exams, perhaps 15 years ago.
BTW I did some research into the Jackeroo you mentioned, to little avail. Could it be you meant a Thruxton Jackaroo?