Most of the time you can get away with using the Google USB drivers that come with the SDK.
For some reason, the Telstra Uno only showed up in the Device Manager as an unrecognised device "MT65xx".
First off, this post by Andweeb showed me to a viable set of drivers.
Download usb_driver_MT65xx_Android_ZTE_v821.rar and extract them somewhere easy to access.
Now open up the folder you extracted it to, click through to "usb_driver" and edit "android_winusb.inf".
Depending on your operating system (x86 or x64), paste this under either "[Google.NTx86]" or "[Google.NTamd64]" respectively.
; Telstra Uno ZTE T12
%SingleAdbInterface% = USB_Install, USB\VID_19D2&PID_0260
%CompositeAdbInterface% = USB_Install, USB\VID_19D2&PID_0260&MI_01
Save, then use the edited inf file as the driver. Then you can enjoy debugging on this awkward, semi-passable phone.
Almost as awkward as this.
The links which almost helped.