Chris Brame wrote:
OK, here we go - start with the little Grumman:


Some of the shots are nearly identical to mine.
"the little Grumman" was neither "little" (as far as G-21 series aircraft are concerned) nor a "Grumman" either. The four-engine McKinnon G-21C conversions were actually "zero-timed" (rebuilt) and re-certified as completely new aircraft under a whole new type certificate (4A24) - at which point they were officially no longer "Grummans" in any way. And as far as being "little" or not, while basic Grumman G-21A Gooses had a max. gross weight of 8,000 lbs, the McKinnon G-21C was certified all the way up to 12,499 lbs - more than half again as much.
I also just found a color photo of its sister ship (s/n 1202) online (I've already seen this same shot in B&W before...)
BEFORE (1967) at GAtwick Airport near London:

and AFTER (2011) at Dhaka Zia Airport in Bangladesh:

Whereas N150M (McKinnon G-21C s/n 1201) had red stripes and trim from 1958 until 1966, N3459C (s/n 1202; later as AP-AUY in Pakistan from 1967 until 1972 and as S2-AAD in Bangladesh after 1972) had blue trim and stripes.
After its conversion first as a long-nose (with 4 extra seats) model G-21D (s/n 1251) in June 1960 and then to have two 550 shp PT6A-20 turbine engines (replacing the four 340 hp Lycomings) per STC SA1320WE in 1965-1966, N150M (the red one in the old 1959 stills above) was eventually repainted with gold stripes and trim.