All great shots Nick but especially photo 6, my favourite, the sort that takes your breath away! One can look at it repeatedly without it ever losing its appeal. The sort of photo that goes on a shelf or desk and never gets moved.
Although at first sight it seems a paradox that a lens can be of high contrast and yet at the same time retain highlight detail I know exactly what you mean - I get the same with my Zeiss ZM Planar 50/2, and incidentally with many of my Pentax lenses. A strange quality.
I've recently bought an ME Super and Pentax M 40/2.8, which although much larger than the Rollei 35 certainly isn't bulky. I'm hoping that the lens quality might approach that of your 40mm Zeiss.