In the mid-70s Britannia, I believe came reasonably close to buying/leasing 2 DC-8 60 series. They even went so far as to nominate key personnel (fleet captain etc.)
Binning the idea eventually lead to the project that saw the 767 being ordered.
I never knew that. The only non-Boeing jet I remember Britannia getting involved with was the Transaer A320 for a couple of summer seasons in the late 1990s.