Hi Hippy,
All arrests are recorded on the police custody systems. If the offence is recordable ( inditable ) then the PNC ( Police National Computer ) will record the arrest, bail and charge or No Further Action ( NFA ) or Insufficient Evidence (IE). This is a Police record and not criminal record. The only offences that are recorded on a criminal record are convictions at court. You refer to a clean slate - I think you mean that you were charged and went to court and were found not gulity. You are therefore innocent of any crime and will not have a criminal record. The PNC record will show the trial and the no guilty verdict.
HOPE THIS HELPS