They did this with their piston aircraft, but it died out with turbine types where they started to use the manufacturers' name instead, the Viscount being the first such.
BEA's practice of naming its aircraft fleets on a common theme became redundant with the introduction of the "red square" livery in the early 60s, which did not have provision for painting individual names on aircraft.
By then, the upcoming Vanguard fleet had been allocated names (based on warships from Nelson's era) but only G-APEA wore (briefly) the old peony scheme and I don't know if that featured its individual name "Vanguard" (which was also the class name).