The Coupé incarnation of Jaguar's ground-breaking XJ saloon didn't peek from showrooms until 1975, although it had been announced publicly rather earlier, back at the 1973 London Show.

Its original design dated from even earlier still as it was developed alongside the original Series 1 XJ back in the late 60s and in fact the company even issued project numbers for the Series 1 Coupés - XJ33 for the six-cylinder and XJ34 for the V12- although they were destined never to be produced.

Instead, the car was launched in Series 2 form known as XJ35 and XJ36 respectively.

However, a combination of Sir William Lyons' frequent tweaking of the design and engineering 'issues' with the roof panel and side windows, meant that it was early 1975 before the first XJ-Cs would glide stylishly out of Jaguar Showrooms.

The Coupé was based on the short wheelbase version of the XJ and offered in 4.2 and 5.3 engine sizes known as either the Sovereign from Jaguar or the Double Six from Daimler.

In 1978, j...