It was inevitable that a coroners inquest would follow the death, and that his acts in altering the database would tend to mislead the Coroner's Court. Typically, they merely remove the index entry relating to that data. The data remains, and can often be found by a competent practitioner. Indeed it is quite clear that there are very substantial traces of much of the activity which takes place on a computer. Computers are good at making copies of almost everything, and of keeping that copy 'just in case' Many files contain very much more information than the user will immediately see.
Word files are notorious.
The ten word note you create, will often occupy 32000 characters. That spare space will be filled with all sorts of goodies - not least often earlier versions of the note. This note relates to English law only. Law changes constantly, and a short note cannot reflect the complexity of real life. Do not rely upon this note alone, but ask about your situation.