There was a small cargo concern at Heathrow called Sagittair, operating 3 (IIRC) Beech 18s....they used to operate mostly at night, often to Geneva. This would have been circa 1970. They then equipped with Argosies (I don`t remember how many) and promptly went bust. I`ve often wondered if this was some ruse, and some sleight of an accountants hand was involved, as it seemed like a radical shift in business model.