The Jupiter was engineered around 1948 and announced at the British International Motor Show at Earl's Court at the end of September 1949. Its factory-based styling, probably done in 1949, seems to have been inspired by the Jaguar XK120, introduced at Earl's Court in 1948. Therefore, it could be considered "advanced" by British standards of the time.
Unfortunately for the Jupiter, even though it followed the XK120 checklist of styling features, the result was ill-proportioned. The front half of the car seemed too tall and the rear half too low. Plus, the front was filled with fussy details.
Jaguar XK120
Jowett line
Jowett Jupiter
Auction-related photos of a restored Jupiter