Don't expect anything and you won't be disappointed
Action Fraud is basically a recording service introduced by the government to take some of the pressure off the police. NFIB also don't have investigative powers. The standard e mail that you will receive telling you that 'it has not been possible to identify a line of enquiry which a law enforcement agency in the UK could pursue' is very likely untrue. It certainly was in my case. A crime had been committed and I had details of the offender and the location of the property involved! When I challenged the e mail, I received a reply from someone (these e mails are not signed) saying 'we will be unable to provide you with further information concerning the decision made due to the sensitive nature of police work...'
What they are really saying is, we know you're a victim of crime and that there is sufficient evidence to arrest the offender but the police don't have sufficient (or properly trained) officers to investigate these offences. (The e mail stated that they receive 50,000 reports a month!)
Also, unless there is admissible, reliable and substantial evidence to ensure a realistic prospect of conviction then the Crown Prosecution Service will not even authorise an offender to be charged.
Basically, it all comes down to ££££, and in the meantime these criminals are laughing, with impunity, all the way to the bank!