On the Roger David shot, are you saying that you exposed at 1600 ASA and developed with standard C41 time? You're a bit short on some detail, and seemingly long on other detail. By the way, if that was shot over the last two days, then, even allowing for electronic methods to get it onto a computer screen which bump contrast, that looks pretty good to me. It has been quite flat weather and to get that contrast you're looking good. As for the blacks not holding their detail, that is a bog standard situation of pushing and/or under exposing a C41 film, if indeed you did push the film that is.

Lucky film is not a premium film, either colour or B&W, although I like and have used both.

An empirical method to find my true speed of a C41 film in my camera(s) exposure and my darkroom developing, is to expose in 1/3 stop increments around the speed I believe it will be. Generally speaking, when viewed under a loupe on a light box, the first frame that has tighter grain structure is the first frame to have ever so slight over exposure from the true speed of the film.

With C41, worse grain (loose looking as well) is under exposed and above the true speed of the film, better grain (tighter and smaller looking) is a byproduct of being below the true speed of the film.

By the way, does your camera fire the shutter within acceptable limits allowing you to rule out camera exposure deviation?