Hi Shane,
Fitting rear seats is relatively straight forward – because our Cabriolets were once Coupe before they were modified by Jaguar.
You’ll have to remove the existing Cabriolet rear locker box, and the left and right side’s “modified” armrest.
Then source a set of XJS Coupe rear seats (see below).
You will also need the corresponding armrests (these have a padded arm rest rather than the tray the Cabriolet has). This link will take you to eBay, where some are for sale – you can easily clean the colour off these and recolour the leather whatever colour you want or leave them black…
eBay link
You will find under the Cabriolet’s rear parcel shelf that the rear seatbelt mounting points are already there – as i said these were Coupes before the roof was cut off and other modifications undertaken.
There are lots of rear seat combinations, that went with various models and years of XJS, so try and find a set which have low rear seat bits – so they don’t get in the way when the Cabriolet’s roof is folded down. Not certain, but a good call might be Convertible rear seats (many convertibles came with rear seats as standard, so not all have the locker box which is similar to the Cabriolets).
Laurence