It was Colin, it's actually quite deep into the cars rear seat backs.. I'm 5.10" in height and my driving position was okay to give reasonable passenger clearance sat behind me, but for a driver who requires more driving space by setting the driver's seat further back, then the rear of the driver's seat to passenger leg room may well be compromised, hence a deeper boot space.
My side by side comparison with the a new UX at the dealership (the car I was going to downsize to) showed that the UX boot was, in my view, looked miniscule.
The other reason for my change of mind from my NX to UX over my NX to LBX was that having had 3 x NX's and kept them for just over 2 years each, I thing the cars are fabulous, but I think the UX being a smaller version of the NX, it was time to go for a different look, and when you see the LBX, it's a new look.. hybrid too, as opposed to all (no thanks) electric.