Focus TDCI Cuts Out - Glow Plug Light On

[Marvindodgers]

Hi, had an experience last night in my Focus TDCI (54 reg Mk1)! M40 in 4th lane at 70mph (!) when the engine cut and the Glow Plug light came on (solid, not flashing). Drifted across the 4 lanes (and the 2 entry slips of the M25!!!)to the hard shoulder, switched off, switched on and car started as normal - no glow plug lights. Drove off and it happened two further times (just dipped the clutch and bump started to clear).
Pulled off the motorway and stopped to read the manual. It didn't say, "stop immediately!!", just consult your Ford dealer, so drove home and it didn't happen again, but the "engine" light was on permanantly (not flashing).
I've looked on the Ford Focus owners forum and their appears to be some thought that it is the cam sensor. For £15 I'm inclined to give it a go.
Are there any other thoughts on this? Also, any idea where the cam sensor is?

[DJ_AS]

Sounds very similar to what happened to my Mondeo 2.0 TDCi. That turned out to be the cam position sensor.

IIRC, the sensor lives under the engine cover somwhere (paid a garage to do the work so never really had a proper look) and I changed both the sensor and attached wiring. I read that this was cos the new sensors work at a higher voltage. The guy who changed it thought it wouldn't make a any difference but I insisted (despite the fact that the wiring cost more than the senser - go figure).

[NST]

i had the same thing happen to me (54plate TDCI), only after about 5 restarts it got worse and worse to the point it would start then die again straight away.
it turned out to be the high pressure fuel pump.