Decided the Nexus 4 needs an upgrade and was torn between the Xperia Z3 Compact and the 'normal' Z3.
Leaning towards the Compact as it's £150 cheaper, has nearly identical specs bar the screen resolution (which is barely noticeable on a 4.6" screen anyway), and I reckon it'll be more comfortable to use one-handed anyway.
The N4 at 4.7" was perfect, and while this is *very* slightly smaller, I doubt it'll be noticeable. All of the other specs are an upgrade (4G which is the main one, better camera, expandable memory).