Difficulty in differentiating the 420/Sovereign from other Jaguar/Daimler models has meant that they are less well known than other Browns Lane products of the era. Even some Jaguar enthusiasts are unsure exactly where and when the 420/Sovereign fitted into the Jaguar range.
At the same time as the 420 was released, Jaguar added a chrome side strip and side repeater indicator to the Mark X and a centre bar to its grille. Along with alterations to the interior, these changes were used to justify renaming it the 420G ("G" for Grand). The Motor magazine of October 1966 referred to the 420G as "...still one of the best looking large cars in the world today" and commented on the similarity of its new radiator grille to that of the 420. Given the similarity between both the names and frontal styling of the 420 and 420G, the casual observer might be forgiven for mistaking one for the other.
In 1968 the Daimler DS420 limousine began to be produced, carrying a similarly styled grille to the Sovereign and using the 4.2-litre Jaguar engine in twin carburettor form and also undergoing final assembly at Jaguar's Browns Lane factory in Coventry, England. Although this car was based on a modified 420G floorpan rather than that of the 420, the existence of a third Jaguar-manufactured model with "420" in its name provides further scope for confusion.
Similar confusion arises with regard to the Daimler Sovereign. From late 1969 its Series I Jaguar XJ6-based successor continued with the Daimler Sovereign name until 1983, when the "Sovereign" model name was instead applied to the high-specification version of the Jaguar, (which by then was into its Series III XJ6 iteration). Detail of subsequent bearers of the Daimler Sovereign model name can be found in the article on the Daimler Sovereign.
Read more about this topic: Jaguar 420 And Daimler Sovereign (1966–69)