Firstly the primary purpose of the glow plugs on a direct injection diesel engine is not for cold starting, unlike on an indirect injection engine. It's for improved emissions and noise reduction when the engine is running cold. However, they do switch on for preheating when the outside air temperature is below 0°C.

Check to see if there's white/grey smoke puffing from the exhaust when you crank the engine from cold. If there isn't then fuel is not being injected, and most likely you have a fuel drain back to the tank overnight. If there is smoke then the inducted air may not reaching the temperature required for the fuel to vapourise. In this case you could have low compression. Or you could have a restricted air intake or a stuck open EGR valve which would give a lack of air or lack of oxygen due to drawn back exhaust gas.

This is excellent, thanks all.

Yes, started fine when bumped and runs fine all day once it's been going a few seconds. The girl drain thing makes sense, will check for the white smoke.

If it started ok with a bump, cant see this being a fuel drain back issue.

The OP has not posted on the Forum for 4 years, so I doubt that you will receive a response from them.