starting problem?

Hi all,

My partner van which is R reg has trouble starting in a morning.It turns over for ages then just starts and is quite smoky. I have tried leaving the glow light on 3 times but no good.It starts great after that through the day,but if left all day and i try and start it around 5 o clock,it is the same as if starting it in the morning. Has anyone got any ideas please cos itd doing me bonce in.