Update: I still couldn't get in to Qobuz via Sense but emailed Innuos Support yesterday afternoon, and received a reply this afternoon.
The solution was to find my Zen Mini interface on my home network, via web address, then try and login to Qobuz via web.
Anyway, worked perfectly. I feel a bit stupid that I didn't think of this myself; a bit of a Homer Simpson moment DOH!
But, apart from that, great customer support from Innuos 👍