I narrowed it down a bit more, no leaks around glow plug, it seems that it runs fine while I have the glow plug ignitor on, so I replaced the glow plug, still the same, rumour tells me that it must be running rich on the low speed needle, so I slowly wound it it in until I got some joy, it meant that I had to lower the idle speed as it started to run away with no throttle input.
What mystifies me is why I have to go so lean on the low speed to get it to run!!???? [&:]