Well, I've taken the plunge and bought a 15-reg NX300h with an exceptionally high spec - head-up display, forward radar, sun roof, heated steering wheel, etc, etc; one careful lady owner (yes, really) and looked after by Lexus Swindon since new. It's a real find, immaculate, and being an SUV it's much easier of access than the IS. Lexus did apart-exchange deal for me, not a good as I'd naively hoped for but good enough.
I'd be interested to learn what typical MPG other NX300h get. It's a heavier vehicle, albeit with the same engine as the IS, but I'm not going to get 50+ on a long run - or am I? , What's the best I'm going to get in a mix of highway and truly rural motoring (we're in the middle of Wiltshire).