Is there any cctv ?
Apart from the police, is anyone complaining about your manner of driving ?
Are you the only person to be reported, I appreciate you may not know this.
As default, if you go into the back of someone, YOU are always blameworthy, that is why you have been reported.
Did you say this " because I was watching the vehicle to my right I didn’t give full attention to the front hence the crash " in your police witness statement ? I am unsure as to why you would come onto a public forum stating this and then ask for advice. Inadvertently you have now damaged your position, should you have wanted to consider challenging the offence.
S.3 of the road traffic act - Careless, and inconsiderate, driving is as follows :
If a person drives a mechanically propelled vehicle on a road or other public place without due care and attention, or without reasonable consideration for other persons using the road or place, he is guilty of an offence.
This is what the police must apply to your manner of driving to be successful in convincing the courts that you are guilty. This particular section of the road traffic act is not one that is easy to prove and the CPS are often keen to avoid it unless absolutely necessary. It is not for anyone to guide you in anyway, but in consideration of what you have said initially, it appears that such was the hard braking from the vehicle in front, for whatever happened ahead, that you were left with little option. Of course, your distance from the vehicle in front will come into question, but in isolation of other factors contributing to the accident, does that prove that you drove carelessly.
You are well within your rights, to reject any responsibility for the offence for which you have been reported and represent yourself if you are in financial difficulty. Only cctv will prove your distance from the vehicle in front, unless of course there are other witness statements that all corroborate together what your approximate distance was from the truck in front.
Had this been myself I would have challenged it without hesitation as it appears the police have used a blanket tactic to report all concerned, hence the easy option for them of a short learning course.
I most certainly would have spoken to a local solicitor and had the free consultation on the matter, but given what you have said in an open forum it may be wise to re think your position.