If, as is likely, the chargeable offence is breaching the Data Protection Act I'd probably rather plead guilty to that than be on trial for obstruction of justice or perjury

The thing is that once you get to criminal charges, everyone is looking out just for his own head. The IT guy who will be asked to delete files couldn’t be gotten on election tampering, so he’s not going to commit obstruction of justice. And if you delete files such that the files are gone but the fact that you deleted them remains, then the government can implicate you for literally anything, so unless it was the worst of the worst crimes like child sex trafficking you’re probably better off pleading guilty to the offense.