My understanding is;So My query really only further confuses the issue- If you have missed 10 payments of €1500 (monthly repayment) - say €100,000 MortgageLoan- of which 1000 is capital and 500 is interest- thereby creating an arrears balance of €15000 . Loan outstanding at start of year was €100,000-

is the total debt now €115000 or €105,000?

If you owed €100K on 01st January and you missed 10 repayments of €1,500, then on the 31st October you would be in arrears of a bit more than €15K, as the outstanding balance is slightly higher each day, there would be slightly more interest applied each day.

Your total debt would be roughly €104,245. (Assuming an interest rate of 5%) as Interest is calculated on the outstanding balance on a daily basis.