Thing wouldn't start; checked fuses & glow plugs/solenoid, removed & cleaned up injectors - nothing seemed wrong, but mechanic friend said he thought the fuel booster pump in the tank didn't sound right. Changed the pump (and solenoid (15-pin, brown, behind battery)) and - hey presto! - problem solved. Happy to discuss the pitfalls of doing that (e.g. how d'you deal with 70L fuel from a full tank?). BTW vehicle mileage is 82,000miles.