When idling I hear a ticking, which I find slightly disturbing. And my oil sensor is completely unusable at the moment. It says "normal" whether the oil is overfilled or underfilled.

 

Try MoscowLeaper's suggestion on the oil sensor.
You have nothing to loose and few hp to gain doing the following.
Run 3 bottles of this https://www.crcindustries.com/produc...-oz-05815.html through the tank to clean out injectors.
drive 1000 miles. *this will help eliminate injectors from the equation, and its a guarantee that your injectors need cleaning if you havent done it yet, could be the ticking you are hearing at idle)
Add this to the oil for 5 minutes before changing it.
Run this oil for 3000 miles and use same flush again

 

Have you ever tried to re calibrate your oil sensor, have you ever done an oil check with you sensor with the hood open ie in service mode?

 

When I bought my new (to me) 2014 in 2018 it had only covered 600 miles in the last 2yrs and hadn't been serviced at all (caught up in probate and kits squabbling over estate)

So I booked it in for a major service ASAP and paid an extra £99 for a full oil flush (normally £199 on a machine that uses hot/cheap oil to flush through) where they connect to the top of the oil filter housing and to the sump. What was in there was so congealed it actually clogged up the machine and made it fail!! They'd not seen anything as bad before. so they did it again at no charge when the machine was repaired by the agent later that day. Appreciate this was on a 2014 car with less than 50k miles.

So hopefully I've got all the cr@p outta mine

 

Marky 7 years ago I had the timing chain problem. Noise at startup that went away after pressure built. They said it was the tensioner and faulty Jaguar design. I refused to believe it on a car with so few miles. It was under warranty, would not have cost me anything. I did not want it to go through surgery so early in its life and lose the factory build quality. (you know glue applied by ham-fisted hands vs a machine) So I tried the cleaning realizing I had nothing to lose. Could not believe it solved the problem, prompted me to join the forum here and share my experience and here we are 7 years later and same tensioner.

In the passing of time there have been several articles written about soot blocking passages, something I was guessing at best. Posted one of those links above.
The best indicator of the soot is the injector fail rate. Another discovery that was not realized till recently. DI was new. little was known and Jag was one of the first out with it.

 

Is this "complete" oil flush service common or only at dealerships. I bought my 2010 XKR at 87K with very limited service history so the flush may be something I'd like to do also. Thanks