Hello the whiz
My understanding is that your friend has completed a Form 3019. There is a difference between the PNC file and the arrest file that police have. My understanding is that all arrests remain on file indefinately. I believe he has had a basic disclosure come back as clear.
If he wants to work where there could be vulnerable of young people the employer would conduct the following type of CRB.
Standard Disclosure
This contains information about both spent and unspent convictions, as well as cautions, warnings and reprimands. It is available in relation to posts that involve regular contact with Children and other vulnerable groups. It also checks information held by the DH and DfES. Standard disclosures are also issued to people entering certain professions, such as legal and finance professions, to name but two. This Disclosure can ONLY be obtained through a Registered Body to the CRB, not by the individuals themselves. I cannot see why he would be predjudiced against for just a caustion unless it was involving violence or sexual offences.
I had the need to apply to have an arrest removed and was successful after one year. The case was seen as exceptional and my dna, fingerprints and PNC record was erased. The arrest record however remains which I think is a disgrace.
Best of luck