I left the UK back in 2010 as I was needed by my family back in my home country. I left suddenly and did not pay my bills and debts before I left. I have not heard from anyone I owe, but a few months after I left my flatmates contacted me to pay my share of the rent, which I have not done. That was almost 12 years ago. I left unpaid credit cards, a mobile phone contract, and my share of the rent. I now have a job offer back in the UK, and have been vetted and approved for a work Visa. Am I going to be stopped at the airport for unpaid bills and not allowed into the UK?
I can understand your concerns and apprehensions, however, the fact you have been approved for a work Visa is a good sign in itself.
Unless there were crimes committed, and charges filed, you would not have been approved for the Visa, and you will not be detained or stopped upon entering the UK.
Due to the time that has passed, your accounts/debts should be Statue Barred, meaning they are no longer owed.
If you have no contact from a creditor for six (6) years, the debt is said to be Statute Barred and no longer owed.