Unless any of the other circumstances apply as you’ve listed above you keep the records until the person’s 25th birthday. This is to allow time for any clinical negligence claims to be brought and to ensure that notes are available for evidence. The statute of limitations means that there is a limited time in which a person, once they become 18, can make a claim, which is why they can be destroyed at 25 years. 8 years applies to adults (again unless any of the other circumstances above apply).
I hope that’s what you were asking!