I have a glow plug on #4 go down with an open circuit. On really cold days it is notably lumpy on start up for around 30 seconds. Reading around it is recommended that when one goes you should replace all as the others will likely follow soon after.

There is precious little on the forum regarding glow plug changing. #4 is probably the easiest one to get to and a Bosch plug looks a good buy at around half the OE Land rover one. So, has anyone ever replaced their SDV8 glow plugs? I asked a garage about doing it and they said best left alone to avoid the chance of having it snap and then require machining out of the head. I usually do my own work but figured because of the snapping issue with glow plugs it'd be best done by a garage who you'd hope would have the counter drill and removal kit to safely get broken glow plugs out.

So, best left well alone (the car has no problem starting after all) or tackle it with a low setting torque wrench after lots of heat soaking of WD40?