Well, I had my oil changed on my XJ 2.7 Tdvi originally around mid February when I bought the car for peace of mind.

Due to the many stop / start journeys around town and the failure to complete the regen process, thus dumping fuel into the system, I was always careful to look after this.

The service light came on requesting service again around June / July so I obliged with a change and reset the system. I did of course only top up to around the halfway ( just under ) and all was well.

Just had another service request on the dash last week, so had another oil / filter change completed and reset, so probably getting around 4 months or so before it tops up and trips the system to request a service.

Its no major biggie and I'm happy to keep on top of this and fresh oil isn't a bad thing, just an FYI for those diesel owners with similar usage.