As much as it irks me to say this, suggesting there is evidence admissible in court that is being destroyed or that an audit instruction is actually a mass cover up is over egging the pudding.
If the elders were destroying paperwork that they were required to keep by law (e.g. financial information related to records required by the Charities Act) then this would be something that may result in court action.
Take a more pertinent example however - an allegation of child abuse. There are no records that the elders are required to keep by law. What is the evidence that is being destroyed? There may be questions asked about the position & actions of the elder and the organisation but in itself I am not aware that any criminal act would have been committed. What could cause a criminal problem is if an elder lied under oath, perhaps denying an allegation had been made. A criminal investigation could also occur if the authorities thought there was a systematic cover up of known abuse to protect individuals or the organisation. Another potentially criminal act would be for an elder to destroy real evidence of a crime (e.g. some photos). The elders in the UK are not under any mandatory reporting legislation therefore there is nothing they are required to do or keep hold of that would constitute a breach of such legislation were they to fail to act or keep certain documentation.
The fundamental intent of the WTS in it's instructions to UK elders is two fold. Firstly, it is to keep the amount and type of information held about individuals to an absolute minimum, especially where some kind of judicial matter is concerned. They do not want individuals making data access requests, getting hold of the musings and opinions of elders and then using that in a civil case against the congregation.
Secondly they want to keep any data that may be used in a situation such as the Royal Commission to an absolute administrative minimum. So, for example, a "known" child abuser would have sufficient information held to indicate to the authorities a measure of due diligence but not enough that would give an alleged abuser an opportunity to bring some case against the congregation.
The important factor here is the motivation behind what information the elders are asked to keep and how they are asked to store it. They don't want some ill considered comments in a document written by a dunder headed elder coming back to bite them on the arse. There could full well be wider implications should something like a Commission or Tax Enquiry take an interest and this will be in the WTS' minds.
I would love to know what the latest instructions are to the elders on record keeping as it is this that will betray the real methods that the WTS is using to cover it's arse for every eventuality.