Thanks for conjuring boyhood memories, Tableview.
Flown SLF in both those big pistons. The L749 preceded the DC7B by many years, so I'm guessing the seventh picture - which seems to have a Seven in the background - might have been around 1958? The Connie was coming to the end of its career by then, IIRC. Remember them at their peak, transiting Lusaka (City) in 1953-5. Firing up in the dusk was an impressive sight, and there always seemed to be one donk that needed a second attempt (after a suitable pause for draining).
The 800-series Viscounts came much later than CAA's 748Ds (1956/7), but I can't remember when.