C5 Starting fault

[imperial21]

I have noticed that my C5 has started to have a funny starting fault, When i try to start it in the morning i turn the key as usual at the point where the starter motor should start it does nothing, If i turn the key backwards and forwards a few times it will start fine, Could this be a starter solonid or ignition switch fault ? Only happens when cold eg in the morning and gets worse in the colder weather or if the car has nt been used for a couple of days, I am sure the battery is fine, its nearly new and i dont think its anything to do with immobiliser as it beeps when that says the key is nt right. My C5 is 2ltr HDI.

[wheeler]

Put a voltmeter or test lamp on the starter solenoid wire whilst someone is trying to start the car & see if there is power going to it, if no power there then most likely an ignition switch fault, if there is power there then most likely a starter motor fault. The immobiliser on this car doesn't inhibit the starter motor so you can rule that out for definite.