Agree. It is unfair. When a single offence is disclosed, to the CPS's standards, the man must be charged with it immediately. When other offences are suspected, the man may be bailed pending enquiries and must be charged as soon as the evidence supports each.
If not one single offence is disclosed after all this time ,the man is in the position of having been arrested on reasonable suspicion but that suspicion has proved unfounded. Ordinarily, the man would be released without charge. Why these suspects are not treated as anyone arrested would be, is not clear. It may be that the defence see an advantage in all this. The longer this goes on without charge, the weaker the charge will appear to be when it is finally laid; you can hear counsel getting ready to say that the prosecution were so embarrassed by the suspicions proving baseless that, rather than admit that, they decided to charge on evidence they had previously realised was inadequate or had desperately dragged up a charge at the last minute, when it would never have passed any test if it the supposed evidence had been there earlier.