Apart from the fact that veg runs a bit hotter John, should make no difference at all to glowplug life. However..
It'll be worth checking the controller is good and they're not remaining on all the time. Conceviably, if the post-heat function was unhappy, they could carry on glowing for all the time the engine is running and this would seriouusly shorten their lives.
The deposits look like polymerised veg to me. You can see it on the injector threads and around the head. If that cylinder was strugging to fire, it'll build up. In an IDI engine, nothing to worry about as it won't reach the piston but it's this polymerisation that kills a DI engine running on veg. It gums up the rings, gets into the sump and turns the oil to jelly
In an IDI it gets destroyed very effectively in the inferno that burns in the pre-chamber. I was not aware until recently, but the bottom of the pre-chamber glows red-hot when the engine is running, hence why it is not unusual to see little radial cracks extening from its throat.
In short, it looks bad John, but nothing to worry about at all. It's just a very devil to clean off.
