On Thursday the warning came on, with the engine well warned up after a 10 mile run. No limp mode or anything, and as soon as she stopped and restarted the light went out. Then on Saturday she got the same thing again, this time on a cold engine, but this time the engine died and she couldn't restart it. I got it started half an hour later, but it took a bit of coaxing.
Ever since then it's been fine. The garage says it can't find any recorded error codes, so it's just a case of wait and see. They've checked the fuel filter and the brake lights and all the other weird things that can produce a glow plug light.
I should say that my missus has a heavy right foot and does more than enough fast running to rule the DPF out. But I've given it a quick 15 minutes @ 3,000 revs in third just to warm it up a bit. Is it worth me using an additive to clean out the EGR? (And do they work, and are they safe?)Cheers