Plod and ACPO are too involved. They should butt out of the process.
Plod is little different to anyone involved in computers - they HATE deleting data.
Why is Plod even involved in the records deletion decision making business?
Let's take Canada. It uses the British (common) law principle and it has a great working systems of criminal record handling.
Assume you are convicted of any offence you criminal record remains until after, I believe 3 years the sentence is completed. In the event of a conviction of a felony the conviction remains until 5 years after the sentence is completed.
To have a criminal record suppressed, and I mean really suppressed from the preying eyes of Plod, an application is made by the individual to the Federal Parole Board (as opposed to the provincial boards).
These guys are in the forgiving business: they have street creds on both sides of the bars. They are the guys who let inmates out on parole AND they grant criminal record suppressions. Only a minister can overturn their decisions, say, for example, continued criminal activity.
In UK the usual prejudiced/biased suspects are involved and even after 25-35-whatever years following a persons last criminal conviction they don't issue a 'clear/clean' record there are either the old convictions remaining or, in the case of records for immigration to other countries, a code that indicates to these countries there is a criminal conviction although expired.
Does this really incentivise someone to go straight? I submit not, The UK should adopt the Canadian model as it has a good track record and has been in effect for decades.