Had this happen 4 or 5 times over the last few weeks

Car usually starts ok in the morning, seems to drive fine. I can then stop eg for fuel or whatever and then she won't start again. This occurs randomly it seems, whatever the temp/time of day. Can happen after 5 hrs motorway driving or 5 mins round the corner.

When it happens she will turnover and start but then seems to be 'gasping' with no response from the throttle before dying within 10 to 30 seconds. Usually if I wait for a few mins, and then keep trying to crank her over eventually she will start with a big blast of white smoke from the exhaust. After that she then drives fine again as if nothing happened.

Bit puzzled by it all. Fuel filter changed about 3 months ago. No leaks anywhere so far as I can tell. Think the pump is working ok. No warning lights on dash. Does her usual 40 odd mpg. Glowplugs seem to be ok. Thinking temp sensor / thermostat may need a change as tends to hover at 70 for ages before getting to about 85, rarely gets all the way to 90. Would that affect the starting though? Heater works fine. Read about headlight switches causing starting problems - this doesn't seem to affect my problem at all though

Any thoughts? Appreciate it