hi
i'm no expert in iphone stuff, but I think what you need is airplay or bluetooth streaming. Unfortunately, Naim UQ2 will only be featuring bluetooth on models starting from this november, so it's either waiting a bit for that OR using AirPort Express or whatever that apple thingie is called (or Apple TV) hybrid audio out with an optical cable into the UQ2 digital input.
The choices are rather weird though, since the Minx XI is like half the price of the UQ2 - so I don't really understand your budget. But, imo, either of these options would defenately be a step up from the zeppelin. Also, if the Quads are not already bought or set in stone, I would also suggest auditioning B&W 685 s2, Dali Zensor 3, XTZ 93.23 mkII - and, for more expensive alternatives, Neat Iota, KEF LS50 and Focal Aria 906 (at least to partner with Naim). And, of course, if the budget allows it, I would defenately go for the Naim Unitiqute 2 or even the Unitilite.
But go to a dealer and audition, you should be the one to decide - and trust your ears 🙂