Anyone with the workshop manual probably found with it some Technical Guides, such as:
JJM 18 15 99/10 XK XJ Stype 2001 Update.pdf (Aug 2000) 58pp
Technical Guide
XK Series, XJ Series
and S-TYPE
2001 Model Year
Update

There are lots more, which perhaps people don't know about, which can sometimes be bought from ebay, can probably be bought on paper from a dealer or can be downloaded from jag's GTR / TOPIx web site. Here are some (Note: the "18" is the jag country code for USA, 10 is UK, etc - no I don't know them all!):

JJM 18 15 16/25 (Jan 2002) 204pp
Technical Guide
S-TYPE
2003 Model Year Update

JJM 18 15 99/50 ~74pp
Technical Guide
X-TYPE Estate
Introduction
Plus X-TYPE, S-TYPE, XK
2005 Model Year
Updates
January 2004

JJM 10 15 16/47 101pp
Technical Guide
S-TYPE
2.7 V6 Diesel Engine
Introduction
2004.75 Model Year
June 2004

JTP1050 03/2005 48pp
New Product Introduction
2006 S-TYPE
Technical Guide

and the early ones partly on some sites:

JJM 10 15 16/92 Jaguar S-TYPE 122pp
Technical Guide
Sports Sedan
Introduction

JJM 18 15 17/92 68pp
Technical Guide
Jaguar S-TYPE
Sports Sedan
Powertrain
Introduction
February 1999

There are others for XJ, XK, X-Type and so on.

Also, Electrical Guides (again, some are with JTIS).