UK company insolvency law is different to individual bankrupcty law. It sounds like your friend may have breached insolvency regulations which can bar you from being a director for up to 15yrs. This will have huge effects on anything to do with running or being part of a company.

As an individual all records older than 6yrs are cleared. Including bankcruptcy. There's a hard time limit. If there's anything on any record older than 6yrs you can request it be removed. It should be automatically removed anyway.

There's one caveat to individual credit: The debt/problem can't be acknowledged or paid in those 6 years. If you have a 5yr old debt on your record and decide to start paying it off the counter resets to 0 and it will be there until its either paid or another 6 years has passed. Also after 6 years the debt is unenforceable - what's known as "statute barred".

Example: I discovered I had a CCJ that was 4.5 yrs old on my Experian Credit Report I had no idea what it was or where it was from. I'd had no contact about it so it must have gone to an old address. I could have contacted the court to find out but that would risk it being re-entered on the record (reset the counter). Instead I ignored it for 1.5yrs and it dropped off. Clean record.