The info you are giving is for negative vetting, ie, a look-up will be done to check that there are no connections with known security risks (eg Al Q, North Korea, IRA etc.), at the addresses you have lived at while you were there.
I doubt they will do a credit check of any sort. That may come later if you are to be cleared above Secret, called positive vetting, but then a case officer will go over all of your history. You will then be able to show that you discharged your debts, and most importantly, that you are not at risk of blackmail etc. by virtue of needing more money than your RAF salary.
I think you can relax.