I'm at 92K miles now on the 2017 TD6 - running impecabbly. I did get the famous : "No start in 250 miles" message a few months back. I had the DEF nozzle replaced, it was completely gunked up...and I also upgraded my GAP IID tool to Generation 4, so I can manage more DPF related activities besides only the Regen, which also includes resetting this error message if needed...although I've been lucky enough not to have to do it as the shop I had replace the nozzle also had the software to do the sequence of resetting the DPF and the couple of steps needed to reinitiate it all.
I've gone now about 8K miles since the dreaded 250 mile message and zero problems with the DPF. I've done 3 long trips of 3500 miles each this year also towing a motorcycle trailer/bike in 2 of those trips and a fair amount of offroad adventures in Colorado as well, and I take advantage of those long trips also to do a DPF regen, which sometimes reaches 12 to 13 and after about 10 miles is back down to 1 or less.
I've seen the process of removing the whole DPF system which is a great long term solution, but I'm not keen to do that yet unless absolutely necessary. The dealership will for sure want you to replace all kinds of parts at a very expensive price point as they just "guess" what to replace.
My cost: nozzle cost at Land Rover club pricing from my local dealer and 1 hour of labor from my local mechanic to replace the nozzle plus 1 hour of re-programming charge...problem solved for about $550 in total parts and labor!
On a separate issue, I did also just do preventative maintenance of replacing all fluids in both front and rear differential, transfer case and transmission, and just a couple of weeks ago I needed to put in a new air compressor for the suspension...not an uncommon occurrence...I had to replace these also on my prior 2 RRS's around 90K as well.