Regarding the cab design, the original had a definite vertical emphasis with the sharp central window bar sweeping down into a nose. It looked like it had a bit of a sad face with puffed out cheeks and actually rather reminiscent of Rev. W. Awdry's Fat Controller. By contrast, the HST front has a definite emphasis on the horizontal with its rectangular windscreen and prominent chisel edged nose, having an altogether more business like and cutting edge appearance.
Unless the HST fronts were to have re-moulded attachments I don't think they will ever look like the Met-Camm originals, no matter how much the paint work is played around with. I'm quite sure that the powers that be at LSL must have really scratched their heads over the cab design issue and as a re-creation, the design was always going to be a bit of a compromise.