I'd also highly recommend this site... http://www.fueleconomy.gov/feg/bymanu.htm
it's for USA market vehicles, but I doubt your XJ is much different except for the extra marker lights, everything being liters and Km, and much better rustproofing in your parts of the world.
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My Fleet 1996 XJ "Snowball"- 3.5" lift, bunch of little mods. I hate pegleg rear axles! 1974 AMC Javelin "Jade Grenade"- 360v8, 4sp, green inside and out. Underfunded Project. 2009 Kawsaki Vulan 900 "Rocket III"- Summer DD