I recall going on a course donkeys years ago when this was discussed with a barrister. Now don't quote me on this due to my loss of grey cells over the years but it went something like this.
Records should be kept for 18 years after the life of the device.
However, records where a child is the subject of an adverse incident should be kept for 21 years. This was based on a child being a baby. The parents could sue on his/her behalf until the baby reached 18 years and after that, the now adult, could sue in the own name for a further 3 years.