My memory seems to think there was a few 2.8 xjs made !!
You could well be right Dean, given the famously random nature of the production line in those days you wonder which other "unexpected" combinations may have escaped !
My father bought an Austin Maestro HLS at one point and it arrived with HLE external spoilers and some VDP trim parts. We had to go back to the show room to check which bits were wrong and then found out the showroom car was also wrong to the catalogue. Nuts.
