@Konceptual - you are 100% correct.
I speak as a U.K. ex elder/ex secretary and as a member of a service committee who sat and went through our congregation records in around 2000/2001 and complied with the branch direction.
EXCEPT FOR CHILD ABUSE CASES - All judicial records (envelopes and contents) were read, noted and destroyed and the basic dates and actions became a one line entry on the "specialised shepherding list". This actually benefited those on the wrong end of a J/C whose notes included how many times they rogered each other and other gory details.
CHILD ABUSE CASES - all records were sent to the branch and the basics were to be put on a congregation "Child Protection File" including whether the "authorities were involved" and who the "alleged victims were" - WHETHER THERE WAS A JUDICIAL CASE OR NOT. A one witness allegation should have been included on this file whether a J/C occurred or not.
I know this for a fact - I kept the files myself as Secretary from 2000 until my resignation in 2004.
EVERY YEAR SINCE a reminder to destroy elders notes as per the form has been sent to the BoE and the Service Committee primarily via the Secretary were to check it had been done.
ALL details of OLD AND NEW CHILD ABUSE CASES WERE to be kept and/or sent to the Branch. Not destroyed.
Looking at Australia and the ARC and their successful subpoena of so many records and elders letters/notes I believe the Branch kept them.