This isn't going to answer your question I'm afraid, but might help with the starting...
I have a Pug 406 for my sins and it is reluctant to start if I follow 'normal' starting practice (ie, if I turn it over as soon as the heater light goes out) and my thoughts went something like this:
1. Battery low? No - got a new one that charges ok and spins for England
2. Some sort of high resistance joint in the heater circuit? (possibly a knackered relay) - possible....
3. One or more duff heater plugs ?
Anyway - the fact is that I have done no furthher investigation since this is just a hack... And anyway I have established through trial and error, a certain way of starting it first touch (well, within a couple of seconds anyway):
What I do is I turn it on and I wait for the heater light to go out and then I count to five before cranking it (usually while putting my seat-belt on). Works every time and reduces the load on the battery and the puff of diesel smoke on start up.
As I said - it doesn't answer the question, but this technique (or something like it) might help alleviate the symptoms in the mean time.
Roger