It is actually a RHD 1990 XJ.
The car belongs to a mate of mine that lives in the US and he has asked me to try and get a RHD drag link in the UK as he's finding it difficult to get one over there. There was a RHD version of the XJ in the US made specifically for the US Postal Service. The reason postal XJ's are RHD is because the mailboxes are located on the side of the road. If the postie had a LHD vehicle, he'd have to be parked against traffic to put stuff into the mailboxes from the vehicle.
Anyway I'm just wondering whether the XJ that started in the UK in 1991 was the same as the RHD XJ's available to the US Postal service in 1990.