I bought my XJ last March and it's been a near perfect car except for the odd fault like DSC not available and the parkbrake fault.
Reading on here about servicing this and that I decided over Christmas and New Year I would do the lot which included:
Air filter / pollen filter
Engine oil and filter.
Transmission oil and bottom cover/filter
All six spark plugs
Front rotors and pads.

All went well I can report, the tranny oil and filter change was a breeze thanks to a great write up I got off here, mine was slightly different in that writer of the article said he put release oil on the Torx screws, my gearbox has blind holes so I expected a right battle with them but they came out really easily. Made a pressure pump at work to put the fluid back in about 5.5 litres.

The hardest part was changing the plugs, the first 3 came out and went in easily, the 4th one not too bad but the last two under the air intake manifold were a bit more awkward.
My car has 102K on the clock and has full dealer service, well they never changed the 3 on the air intake manifold side, I'll bet they charged for it though!
The 6 plugs that came out didn't match and the manifold side looked like original plugs.
I'll now tackle the diff oil change and really need to find out why the phone has stopped working and muted my radio.

Dave

 

I bet you feel good about the work completed.
I have just done my spark plugs (8) for the 2nd time in about 6 weeks as my fuel consumption fell off quite dramatically with Bosch Iridium replacements. Re did them with the original NGK Iridium and am back to around 20mpg around town as opposed to 14-15 with the Bosch.
I need to do all the other work you have done but the temperature here in MD, USA is around 14 F! It will have to wait until Spring. I miss England from the perspective of the severe cold we get here.
I have 102,000 on my 2005 XJR.