Tradewinds
As I mentioned in my original post, my father owned a freight forwarding company in the 80's and for a time ran charters from Prestwick to Hartford using Tradewinds 707's. I worked for the company as a youngster before growing up, getting married and moving to California!
Among other fond memories are flying in the jump seat of G-BFEO across the pond; clambering over cargo pallets to reseal the aft door on G-TRAD; and putting the tail stand on G-SAIL - after the airport employees forgot and started unloading!